WO2024105075A1 - Improved low-temperature sensible-heat ground-storage and heating/cooling system - Google Patents

Abstract

The invention provides an essentially brine free system equipped for heating at least one enclosed space, said system comprising a ground source heat-pump system (HP) capable of servicing said space with heat through a space heat exchanger combined with at least one solar thermal collector, herein also called solar water collector, at least one closed loop essentially horizontal ground heat exchanger, herein also called ground heat storage system or groundnet, at least one pump P1 allowing temperature-controlled fluid flow through said solar thermal collector, wherein said pump P1 is directed to maintain a temperature difference (ΔT) of at most 15 to 2 degrees Kelvin between outlet fluid and inlet fluid of said collector, when outlet T > inlet T.

Description

Title: Improved low-temperature sensible-heat ground-storage and heating/cooling system

Field of the disclosure.

This disclosure relates to sensible heat storage. Sensible heat storage is the simplest heat storage system. It stores the energy in sensible heat, which can be reflected by the temperature. The fluid storage media typically include water and oil. The solid storage media may typically include the building fabric, metal, soil, and rock.

Background.

Thermal energy storage (TES) is achieved with widely different technologies. Depending on the specific technology, it allows excess thermal energy to be stored and used hours, days, months later, at scales ranging from the individual process, building, multiuser-building, district, town, or region. Usage examples are the balancing of energy demand between daytime and night-time, storing summer heat for winter heating, or winter cold for summer air conditioning (Seasonal thermal energy storage). Storage media include water or ice-slush tanks, masses of native earth or bedrock accessed with heat exchangers by means of boreholes, deep aquifers contained between impermeable strata; shallow, lined pits filled with gravel and water and insulated at the top, as well as eutectic solutions and phasechange materials.

Other sources of thermal energy for storage include heat or cold produced with heat pumps from off-peak, lower cost electric power, a practice called peak shaving. Peak shaving involves proactively managing overall demand from the electrical grid to eliminate shortterm demand spikes, which set a higher peak and increases grid-building and maintenance costs. This process lowers and smooths out peak loads, which reduces the overall cost of demand charges. It is often believed that solar + battery energy storage is the best way to peak shave. However, that does miss out on heat from combined heat and power (CHP) power plants; heat produced by renewable electrical energy that exceeds grid demand and waste heat from industrial processes. Heat storage, both seasonal and short term, is considered an important means for cheaply balancing high shares of variable renewable electricity production and integration of electricity and heating sectors in energy systems almost or completely fed by renewable energy. There is thus a need for better peak shaving practices. The power of the sun is not steady and available all day long. It varies with time, weather, and season. The instability and intermittency of solar power make high efficiency and longterm solar utilization difficult. Solar thermal storage is one of the solutions for this. There are now mainly four kinds of solar thermal storage technologies: sensible heat storage, latent heat storage, sorption heat storage, and thermochemical heat storage. TES systems are a key technology that utilizes renewable energy and thermal energy to ensure continuous and stable operation in concentrated solar power plants, family heating, and industrial waste heat recovery fields. It solves the intermittent problem of solar radiation and significantly improves energy efficiency and economic benefits. At present, the most used thermal energy storage system for concentrating solar power plants is based on the concept of two-tank storage that using molten salt as the heat storage medium, and solar salt (a mixture of nitrate and nitrite) are usually used in the high-temperature field. Storage systems using sensible heat storage also have been developed for operation temperatures up to 400°C. These systems are intended for integration into solar thermal power plants demanding storage capacities in the MWh-range. Research has been focused on the development of cost-effective storage systems using concrete with embedded heat exchangers. In sensible heat storage, the storage is based on the temperature change of the material. The unit storage capacity (J/g) is equal to heat capacitance X temperature change. Possible "sensible heat" storage media are liquids (typically water) and solid materials (typically soil and stone. Take water as an example: it has heat capacity of approximately 4.2 kJ/( kgK) and a density of approximately 1000 kg/m3, which result in an energy density of approximately 11.7 kWh/m3 for a 10°C temperature change. A heat pump is a system used to heat or cool an enclosed space or domestic water by transferring thermal energy from a cooler space to a warmer space using the refrigeration cycle, moving heat in the opposite direction in which heat transfer would take place without the application of external power. When used to cool a building, a heat pump works like an air conditioner by transferring heat from inside the building to the outdoors. When used to heat a building, the heat pump operates in reverse: Heat is transferred into the building from the outdoors. Common heat pump types are air source heat pumps, ground source heat pumps, water source heat pumps and exhaust air heat pumps. Heat pumps are also often used in district heating systems. The efficiency of a heat pump is expressed as a coefficient of performance (COP), or seasonal coefficient of performance (SCOP). The higher the number, the more efficient a heat pump is and the less energy it consumes.

Heat pumps (HP) represent a mature and well-known technology for building heating and cooling purposes. In 2014 a total amount of 1.7 million units have been sold in European Union with Sweden leading the ground source market share. A total heat pump capacity of over 6.6 GW was installed for an estimated energy production of about 13 TWh. Only in Sweden, over 1.4 million units are estimated to be in operation and the heat pump represents the most popular heating system for residential buildings, covering, together with electric heating, over 35% of the total heating demand.

Nouri et al (a, Applied Thermal Engineering 163 (2019) 116352) review solar assisted ground source heat pumps (SAGSHPs), also called ground coupled heat pumps or geothermal heat pumps that absorb heat from the earth for domestic hot water use or space heating or store it in the earth from a solar (such as a flat plate collector (FPC)) or air heated source by a ground heat exchanger (GHE, herein also called ground net) with pipes installed horizontally that are in the depth of 1 - 1.5 m below ground or pipes with different shapes that can be put into vertical boreholes with the depth of 200m. Hence, the low-grade energy of the ground surface from the location of the space is converted into high-grade energy of the space itself, be it by heating via so-called radiators, indoor copper pipes or via heating a floor of said space. Excess solar heat from the collector area was not used to directly heat the building in te absence of HP activity. No information is given by Nouri et al (a) to a preferred thickness of said floor nor to the location of heating pipes in said floor, and according to Nouri et al (a) the GHE is required to be filled with a working fluid prepared with a glycol or any other brine, i.e., as typically is used by heat pump systems to allow for relatively undisturbed system use during freezing (subzero) temperatures of the groundnet derived from the working heat pump.

Nouri et al (b. Geothermics 82 (2019) 212-231) puts forward the simulations (but not the actual testing) of combined solar evacuated tubular collectors (ETC) with brine-run ground source heat pumps (GSHP). Flat plate collectors (FPC) were not put forward by Nouri et a l( b) nor were conditions of floor thickness around a floor heat exchanger (FIH) simulated.

Nord et al (Renewable Energy 87 (2015) 1076-1087) examined by simulation a building energy supply system consisting of flat plate solar thermal collectors in combination with an anti-freezing brine-run GSHP connected to a vertical borehole and an exhaust air heat pump for space heating and cooling and production of domestic hot water. Excess solar heat from the collector area could be utilized to recharge the ground heat exchanger borehole during the summer months as is often practiced attempting to prevent freezing (subzero Celsius) temperatures in the borehole. Excess solar heat from the collector area was not used to directly heat the building in the absence of HP activity, and floor heating was not discussed by Nord et al. US2008/0203179 relates to a brine containing hot water and heating system that comprise primary energy heat exchangers such as solar collectors and air heat or geo-thermal exchangers to transfer primary energy such as solar energy to a heat carrier medium termed brine (for example glycol, therewith reflecting all prior art anticipating subzero temperatures of parts of such systems). No floor heating is disclosed in US2008/0203179. According to the 2010 European Performance of Building Directive member states shall ensure that all new buildings constructed after 2020 should be "near zero energy" and building heating systems are now accounting for 40% of the total energy consumption. The residential sector represents the 27% of the global energy consumption and it grew by 14% from 2000 to 2011. Hence, the current and near and far future goal of reducing greenhouse gas emissions involves the study of new solutions to improve the energy efficiency of heating systems in new and existing buildings. Heat pump industry development has reached a mature state over the last 20 years and the research and development potential for further performance improvement of unit components such as compressors or heat exchangers is economically less and less sustainable for manufacturers. On the other hand, the computational power of electronic devices has been increasing together with storage and connection capability. For these reasons there has been a growing interest in the possibility to introduce advanced features in the heat pump system controllers to improve the overall system performance by enhancing the control logic algorithms. Huchteman and Muller ["Simulation study on supply temperature optimization in domestic heat pump systems." Building and Environment 59 (2013): 327-335.] show that by just adjusting the supply temperature from the heat pump based on internal gain, it is feasible to reduce the annual electricity consumption by 6.8%. Several control systems to improve heat pump system performance have been developed and are easily accessible to use and several review studies have been proposed to define the state-of-art from different points of view. Fisher et Madani ["On Heat Pump in smart grids: a review". Submitted to Elsevier (2016)] propose a review of heat pump system definitions and control strategies from the smart grid concept perspective. Afram and Janabi-Sharifi review ["Theory and applications of HVAC control systems - A review of model predictive control (MPC)." Building and Environment 72 (2014): 343-355.] focuses on the comparison of Model Predictive Control (MPC) approach with respect to other control implementations. Atam and Helsen's ["Ground-coupled heat pumps: Part 1 - Literature review and research challenges in modelling and optimal control." Renewable and Sustainable Energy Reviews 54 (2016): 1653-1667.] work contains a review of control methods dedicated to Ground-coupled Heat Pump (GCHP) systems. Dong and Lam ["A real-time model predictive control for building heating and cooling systems based on the occupancy behaviour pattern detection and local weather forecasting." Building Simulation. Vol. 7. No. 1. Springer Berlin Heidelberg, 2014.] presented the results of a test-bed experiment employing over 100 sensors measuring indoor environmental parameters, power consumption and ambient conditions in the so- called Solar House experiment. The experiments were carried out for two continuous months in the heating season and for a week in the cooling season. Local weather forecasting and occupant behaviour detection have been included into an MPC design. The results showed a 30.1% measured energy reduction in the heating season compared with the conventional scheduled temperature set-points, and 17.8% energy reduction in the cooling season.

When used for space heating these heat pump devices are typically much more energy efficient than simple electrical resistance heaters. Heat pumps have a smaller carbon footprint than heating systems burning fossil fuels such as natural gas, but those powered by hydrogen are also low-carbon and may become competitors. Typical are systems combining a heat pump with a ground heat exchanger (closed loop systems) or fed by ground water from a well (open loop systems). They use the soil as a heat source when operating in heating mode, with a fluid (usually water or a water-antifreeze mixture) as the medium that transfers the heat from the soil to the evaporator of the heat pump, thus utilizing sensible-heat stored energy. In cooling mode, they use the soil as a heat sink or heat storage. Ground source heat pumps employ a ground heat exchanger in contact with the ground or groundwater to extract or dissipate heat. Incorrect design can result in the system freezing after several years or very inefficient system performance; thus, accurate system design is often deemed critical to a successful system. Pipework for the ground loop is typically made of high-density polyethylene pipe and may contain a mixture of water and anti-freeze (propylene glycol, denatured alcohol, or methanol). Monopropylene glycol has the least damaging potential when it might leak into the ground, and is, therefore, the only allowed anti-freeze (also called brine) in ground sources in an increasing number of European countries. A horizontal closed loop field is composed of pipes that are arrayed in a plane in the ground. A long trench, deeper than the frost line, is dug and U-shaped or slinky coils are typically spread out inside the same trench. Shallow 3-8-foot (0.91-2.44 m) horizontal heat exchangers experience seasonal temperature cycles due to solar gains and transmission losses to ambient air at ground level. These temperature cycles lag the seasons because of thermal inertia, so the heat exchanger will harvest heat deposited by the sun several months earlier, while being weighed down in late winter and spring, due to accumulated winter cold. Systems in wet ground or in water are generally more efficient than drier ground loops since water conducts and stores heat better than solids in sand or soil. If the ground is naturally dry, soaker hoses may be buried with the ground loop to keep it wet. Jaeger et aL, 1981 (Examination of low-temperature heat storage in soil. Germany) theoretically studied a concept for storage of heat in soil. The spherical ground storage is characterized by a distinctive temperature stratification and thus is especially suited for the storage of low-temperature heat from solar systems. To examine the performance of the ground storage, a program for heat conduction calculations was integrated into a simulation model for solar space heating systems. Jaeger et al. mostly consider the application of the ground storage in a solar energy heated single-family house. Using the simulation program, solar systems with various ground storage and conventional hot water storage systems were compared. The simulations were carried out with time steps of an hour of less for several successive years of operation. In many evaluations, the dependence of the storage performance on different soil materials, heat transfer characteristics and storage size were examined. The Jaeger calculations showed that the initially suggested storage without insulation exhibits too large heat losses. In a solar space heating system, ground storage with insulation is thought to give a somewhat better performance than conventional hot water storage with the same cost. Solar thermal technology can be used in the oil and gas industry to generate process heat or steam. Solar energy collectors transfer the solar energy to a process fluid (typically water, oil, or air), which is used directly (e.g., steam for enhanced oil recovery) or indirectly (e.g., heat transferred in a heat exchanger to another process stream). Several different technologies can be used to heat a fluid by sunlight. Solar thermal energy collectors are typically distinguished by their operating temperature (low, medium, or high) and by their motion (non-concentrating or concentrating). Nonconcentrating collectors (also called stationary collectors) are permanently fixed in place and do not track the sun. They have the same or almost the same area for intercepting and absorbing solar radiation; whereas concentrating collectors track the sun and generally have concave reflecting surfaces that intercept and focus the sun's radiation on a smaller receiving area. Table 1 provides an overview of different types of solar thermal collectors. Table 1

The invention.

The inventor has set himself to provide for an integrated system solution equipped for heating at least one enclosed space, such as at least one house, office, shop, workshop, factory, stable or greenhouse, residential or commercial space, that relies on collecting, using and storing solar energy obtained in the close environment or location of said space, taking into account both the daily as well as the seasonal differences in solar energy obtained from the sun at said space as well in the heating or cooling requirements of the inhabitant(s) or users of said space. For this purpose, the invention discloses a system comprising a heat-pump system (HP), preferably attached to a closed loop ground heat exchange system (GHE, also identified as groundnet) , said HP capable of servicing said space with heat harvested from said GHE through providing heat to a space heat exchanger, preferably a floor heat (FIH) exchanger, and preferably also comprising a means, such as a controller being or having been configured to direct the system according to the invention to collect, accumulate, use and store solar energy obtained in the close environment or location of said space and supervise that above freezing temperatures of groundnet are maintained, allowing highly improved COP of the heat pump. Solar energy is collected by solar thermal collectors (SC) resulting in heated (essentially brine free) water and optionally also by photovoltaic panels (PV) resulting in electricity. In the summer season, when free solar energy is typically most available, said solar heated water is pumped to said closed loop GHE where heat is accumulated and stored in the surrounding ground, typically not requiring HP activity although some cooling said space via HP may also help to accumulate heat in the groundnet. Freely available or inexpensive solar electricity derived from said PV, optionally from battery systems or from outside sources, drives the pump or pumps that help drive and accumulate and store the heat from the solar heated water in the ground. Typically, once harvesting solar energy in the ground is initiated in spring, year-round temperatures of GHE and its surroundings oscillate between 6 and 20 degrees Celsius (in temperate zones, in cold zones those figures are lower but remain above zero. In the spring or autumn season, the emphasis of solar energy use is often directed more at providing the FIH directly with solar energy from SC as sensible heat and PV as electricity required to drive pumping, to heat said space, but typically again not requiring HP activity yet. In the colder or winter season, the HP will pitch in to help heat said space, typically with much higher COP (up to around 7 - 8) and much lower electricity requirements as is usual in common HP (COP up to around 3 - 5) systems, since the GHE return water temperature in the system as disclosed, and thus inlet and outlet temperatures from and to GHE source to and from HP herein typically remain substantially above zero Celsius due to the heated ground around the groundnet that is accumulated via substantial solar energy exchange from SC to GHE in spring, summer and fall.

The environmentally friendly solution here provided renders the system close to CO2 neutral, avoids brine-spillage in the environment, and is very cost-efficient. In a preferred mode as provided in the example of the space heating system disclosed herein an input of at around freely available 16000 kWh/y of solar energy harvested from SC and of at around freely available 11000 kWh/y voltaic solar energy harvested from PV (total freely available solar energy 27000 kHh/y) more than sufficiently allows for a heating requirement output of 19000 kWh/y to heat said space and 2400 kWh output for domestic hot water (21400 kWh/y) , showing that another system of the invention as disclosed here can expediently be dimensioned at an solar energy input : heating energy output ratio of at least 1,5:1, preferably at least 2:1, more preferably at least 2.5:1, keeping in mind that the need for solar energy harvested from SC is considered at least 60%, preferably 70% of input or 70%, preferably 80% of output.

A controller means for use in a system of the invention is preferably equipped to consider and act upon both the daily as well as the seasonal differences in solar energy obtained from the sun at said space as well in the heating or cooling requirements of the inhabitant(s) or users of said space. The system as disclosed by the invention has been tested up to over 7 years to withstand and manage said daily and seasonal differences in energy obtained and required (see also figure 1 and the table in the legend of figure 1), thereby GHE temperatures constantly staying at above zero Celsius without the need for any anti-freeze agent such as a glycol or other brine, and is preferably filled with water as a carrier medium for energy, therewith greatly reducing risking groundwater pollution as commonly seen with other ground source HP systems in temperate and cold zones. Its general principle is harvesting the heat generated by the solar thermal collector at lower temperatures than commonly used and regenerating the ground heat storage system to higher temperatures than commonly used, to finally feed the heat-pump at higher temperatures than commonly used. More directly related to house heating, maintaining above zero temperature also results in a far higher coefficient of performance (COP) of the heat pump, saving considerably on electricity costs. Consequently, the invention discloses configuring the controller on controlling or maintaining ground net (storage) temperatures to above zero Celsius, preferably ground net storage temperatures of 2 - 25°C, preferably 5 to 20°C are configured by said controller, as these temperatures may seasonally vary.

In a further embodiment, in particular to address daily variations or allow for peak shaving on a daily or seasonal basis, the invention discloses a system comprising a heat-pump system (HP), preferably a ground source HP system, capable of servicing said space with heat through a space heat exchanger, preferably a floor heat (FIH) exchanger, wherein said floor in which said FIH is located has or is enriched with a sufficiently high thermal mass, that is increasing the capacity to absorb, store and release heat. In common building practice, such a floor as is preferred herein is a thick concrete floor, preferably said FIH (e.g., the pipes thereof) is covered at least 8, preferably at least 10 cm, more preferably at least 12, more preferably at least 14, more preferably at least 16, more preferably at least 18, more preferably at least 20, more preferably at least 22 cm of concrete. Suitable material to replace concrete are other materials of sufficient thermal mass, such as clay, sand, brick, gravel, stone. Said FIH is preferably layered on top of similar equivalent thermal mass material, if deemed useful supplemented with more isolating materials below and/or as fastening materials when needed. Such a floor enriched in thermal mass allows for improved daily or seasonal peak shaving as discussed further below, thereby reducing costs of heating.

The inventions herewith discloses an essentially brine-free system (essentially here indicating that brine, although in ay be present in the system, is essentially not required since the system avoids running at subzero (Celsius) temperatures often seen in temperate or cold climate zones) and allowing for reduced CO2 emission, said system comprising at least one photovoltaic panel (PV), said system equipped for heating at least one enclosed space, said space preferably located in a temperate or cold climate zone, said system comprising a ground source heat pump (HP) to transfer energy from a low temperature ground heat source to an elevated temperature space heat source by inputting a relatively small amount of electrical energy, said system comprising a means such as a controller being or having been configured to control or direct the system, said system capable of servicing said space with heat in a controlled fashion, said system combined with A) a solar thermal collector (SC) system provided with a drain back tank installed in an essentially frost-free space allowing the drain the solar collectors when they may risk freezing, B) at least one closed loop ground heat exchanger (GHE) herein also identified as groundnet (GN), C) at least one floor heat exchanger (FIH), preferably located in a floor with high thermal mass as discussed below, D) at least one pump Pl allowing temperature-controlled fluid flow through said solar thermal collector (SC) to said ground heat exchanger (CHE) or to said floor heat exchanger (FIH), pending the position of three-way valve VI, as governed by the controller. When the solar thermal collector (SC, preferably FPC) system is not active, the SC pump Pl shuts down, water returns to the drain back tank, thus ensuring the system will not be affected by frost. This drain-back system also prevents boiling due to sudden power failure. In a further preferred embodiment, the invention discloses the system according to the invention wherein said pump Pl is directed by said means to control to maintain a temperature difference (AT) of at most 15 to 2 degrees Celsius, preferably 12-6, more preferably at around 9-11 degrees Celsius between outlet fluid and inlet fluid of said solar thermal collector (SC), when outlet T > inlet T, allowing sensible heat transfer from solar thermal collector (SC) to ground heat exchanger (CHE) or to floor heat exchanger (FIH). In a further preferred embodiment, the invention discloses the system according to the invention additionally provided with a heat exchanger (HE1) capable of transferring heat obtained by said thermal collector to said closed loop ground heat exchanger or said floor heat exchanger (FIH) when said heat-pump (HP) is not required to provide said space with heat, allowing storing said heat generated by said collector in said closed loop ground heat exchanger or in said floor heat exchanger (FIH). In a further preferred embodiment, the invention discloses the system according to the invention additionally provided with at least one three-way valve VI allowing direct routing of heat generated by said collector to said space or to said groundnet. In a further preferred embodiment, the invention discloses the system according to the invention wherein said collector is at least one flat plate collector (FPC), which allows easy drain back. In a further preferred embodiment, the invention discloses the system according to the invention said pump Pl is directed to maintain a temperature difference (AT) of at most 12 to 2 degrees Celsius (Co) between outlet fluid and inlet fluid of said collector, when outlet T > inlet T. In a further preferred embodiment, the invention discloses the system according to the invention provided with at least one additional pump P2 allowing temperature-controlled fluid flow through said closed loop ground heat exchanger. In a further preferred embodiment, the invention discloses the system according to the invention wherein said additional pump P2 is directed to maintain a temperature difference (AT) of at most 20 to 2 degrees Celsius between inlet fluid and outlet fluid of said closed loop ground heat exchanger, when inlet T > outlet T. In a further preferred embodiment, the invention discloses the system according to the invention wherein said at least one additional pump P2 is directed by a heat-pump system controller equipped with sufficient temperature sensors capable of registering temperature of incoming fluid and outgoing fluid of said closed loop ground heat exchanger. In a further preferred embodiment, the invention discloses the system according to the invention wherein pipes comprising said closed loop essentially horizontal ground heat exchanger are essentially installed at a distance of at least 2, preferably at least 3 meters distance from each other. In a further preferred embodiment, the invention discloses the system according to the invention provided with at least one additional pump P3 allowing temperature-controlled fluid flow from said closed loop ground heat exchanger to said heatpump system (HP) is directed to maintain a temperature difference (AT) of 2-6 degrees, preferably 3-5 degrees Kelvin between source input and output of said HP. If the exit temperature on the source side of the heat pump (HP) is <1°C, the activity of heat pump (HP) will be halted by the controller and optionally a notification will be issued. HP is again activated when said temperature is >1°C, preferably >3.5 °C, preferably >6°C. Alternatively, If the inlet temperature on the source side of the heat pump (HP) is >25°C, the activity of heat pump (HP) will be halted by the controller and optionally a notification will be issued. HP is again activated when said temperature is <24°C. In a further preferred embodiment, the invention discloses the system according to the invention provided with at least one additional pump P4 and three-way valve V2 allowing temperature-controlled fluid flow from said heat-pump system (HP) to said space heat exchanger is directed to maintain a temperature difference (AT) of 8-12 degrees Kelvin between space input and output of said HP. In a further preferred embodiment, the invention discloses the system according to the invention provided with at least one additional pump P4 and additional 3-way-valve V2 allowing temperature-controlled fluid flow from said heat-pump system (HP) to a Domestic Hot Water (DHW) tank. If the DHW tank (boiler) demands heat, the valve V2 from the heat pump supply is switched and forced hot water supply is activated. On at <45°C, off at >50°C DHW temperature. In a further preferred embodiment, the invention discloses the system according to the invention provided with at least one additional pump P5 and additional 3- way-valve allowing fluid flow from said closed loop ground heat exchanger to said space heat exchanger under conditions wherein cooling of said space is desired. In a further preferred embodiment, the invention discloses the system according to the invention wherein at least part of said floor heat exchanger is provided with floor heating pipes encased by a floor of sufficient thermal mass to allow for peak shaving, preferably wherein said floor is made of concrete.

Like most scientists, the inventor accepts the scientific evidence that human activities are causing global warming. Despite the uncertainty that in the eyes of some may remain about the sensitivity of the atmosphere to greenhouse gas emissions, notably CO2, which affects the onset and frequency of adverse weather events, this application considers that new heating, cooling, heat pumping and power generation technologies to reduce greenhouse gas emissions need to be developed now. Delaying until the anticipated effects of global warming are pronounced might be too late. This disclosure provides a low-temperature sensible heat storage system for which no ground insulation is required. Its general principle is harvesting the heat generated by the solar thermal collector at lower temperatures than commonly used and regenerating the ground heat storage system to higher temperatures than commonly used, to finally feed the heat-pump at higher temperatures than commonly used. Preferably provided is a system combining a heat pump with a ground heat exchanger (a closed loop system). Said system as provided preferably uses the soil as a heat source when operating in heating mode, with a fluid (usually water or a water-antifreeze mixture) as the medium that transfers the heat from the soil to the evaporator of the heat pump, thus utilising sensible-heat stored energy. In cooling mode, said system may use the soil as a heat sink. In a preferred embodiment, the invention provides a system equipped for heating at least one enclosed space, such as a building, home, school or factory, or at least a part thereof, said system comprising a ground source heat-pump system (HP) capable of servicing said space with heat through a space heat exchanger combined with at least one solar thermal collector, herein also called solar water collector, at least one closed loop essentially horizontal ground heat exchanger, herein also called ground heat storage system or groundnet, at least one pump Pl allowing temperature-controlled fluid flow through said solar thermal collector, wherein said pump Pl is directed to produce sufficient flow to maintain a temperature difference (AT) of at most 15 to 2, preferably at most 10 to 3, more preferably at most 6 to 3, preferably at around 4 degrees Celsius (C°) between outlet fluid and inlet fluid of said collector, when outlet T > inlet T. Preferably, said building is a common home, or parts thereof.

Such as system has provided herein has experimentally been evaluated (see table 1) over several years and demonstrates coefficient-or performance (COP) of close to 6 where common heat pumps systems generally perform with a COP of around3 to 4.

Dimensions for a system as provided herein can easily be adapted to serve the needs of small or large spaces to be heated, as provided in table 3 herein, where dimensions of thermal solar collector or ground net heat exchanger are related to the equivalent of cubic meters (m3) gas projected to be used or used for heating, as calculated for individual places, and may be adapted to individual preferences. In a further preferred embodiment, the invention provides a system according to the invention additionally provided with a heat exchanger capable of transferring heat obtained by said thermal collector to said closed loop ground heat exchanger, at times when said heat-pump (HP) is not required to provide said space with heat, allowing storing said heat generated by said collector in said closed loop ground heat exchanger. In a further preferred embodiment, the invention provides a system according to the invention additionally provided with at least one three-way valve allowing direct routing of heat generated by said collector to said space, preferably to a floor heater in said space. In a further preferred embodiment, the invention provides a system according to the invention, said space located in a temperate (C) or cold (D) climate zone as identifiable according to climate criteria provided for in a Kdppen-Geiger climate classification map (see for example Peel at al., Hydrol. Earth Syst. Sci ., 11, 1633-16454, 2007). In a further preferred embodiment, the invention provides a system according to the invention wherein said collector is a stationary collector. In a further preferred embodiment, the invention provides a system according to the invention wherein said collector is a flat plate collector (FPC), evacuated tube collector (ETC) or photovoltaic thermal collector (PVT). In a further preferred embodiment, the invention provides a system according to the invention wherein said collector is a flat plate collector (FPC). In a further preferred embodiment, the invention provides a system according to the invention wherein said pump Pl is directed to maintain a temperature difference (AT) of at most 12 to 2, preferably at most 10 to 2, more preferably at most 5 to 2, most preferably at around 4 degrees Celsius (Co) between outlet fluid and inlet fluid of said collector, when outlet T > inlet T. In a further preferred embodiment, the invention provides a system according to the invention wherein said at least one pump Pl is directed by a heat-pump system controller equipped with sufficient temperature sensors capable of registering temperature of incoming fluid and outgoing fluid of said collector. In a further preferred embodiment, the invention provides a system according to the invention provided with at least one additional pump P2 allowing temperature-controlled fluid flow through said closed loop ground heat exchanger. In a further preferred embodiment, the invention provides a system according to the invention wherein said additional pump P2 is directed to maintain a temperature difference (AT) of at most 20 to 2, preferably at most 15 to 2, more preferably at most 10 to 2, most preferably at most 5 to 2 degrees Celsius (Co) between inlet fluid and outlet fluid of said closed loop ground heat exchanger, when inlet T > outlet T. In a further preferred embodiment, the invention provides a system according to the invention wherein said at least one additional pump P2 is directed by a heat-pump system controller equipped with sufficient temperature sensors capable of registering temperature of incoming fluid and outgoing fluid of said closed loop ground heat exchanger. In a further preferred embodiment, said ground heat exchanger is an is an essentially horizontal ground heat exchanger or groundnet. In a further preferred embodiment, the invention provides a system according to the invention wherein said pipes comprising said closed loop essentially horizontal ground heat exchanger are installed at least 1.5 meters, preferably at least 2 meters below the ground surface, preferably for at least 75%, preferably at least 90% at least 0.5 meter, preferably 1 meter below average ground water level surface, more preferably essentially or predominantly always below common ground water levels. In a further preferred embodiment, the invention provides a system according to the invention wherein pipes comprising said closed loop essentially horizontal ground heat exchanger are essentially installed at a distance of at least 1.5 meters, preferably at least 2 meters, more preferably at least 3 meters distance from each other. In a further preferred embodiment, the invention provides a system according to the invention provided with at least one additional pump P3 allowing temperature-controlled fluid flow from said closed loop ground heat exchanger to said heat-pump system (HP) is directed to maintain a temperature difference (AT) of 2-6, preferably at least 3-5, more preferably of 3.5 to 4.5 degrees Kelvin between input and output of said HP. In a further preferred embodiment, the invention provides a system according to the invention provided with at least one additional pump P4 allowing temperature-controlled fluid flow from said heat-pump system (HP) to said space heat exchanger is directed to maintain a temperature difference (AT) of 8-12, preferably at least 9-11, more preferably of 9.5 to 10.5 degrees Kelvin between input and output of said HP. In a further preferred embodiment, the invention provides a system according to the invention provided with a 3-way-valve on the outlet of the heat-pump system (HP) to direct HP- heated water to a boiler vessel for producing domestic hot water (DHW system). In yet another further preferred embodiment, the invention provides a system according to the invention provided with at least one additional pump P5 and additional 3-way-valve allowing fluid flow from said closed loop ground heat exchanger to said space heat exchanger under conditions wherein cooling of said space is desired. In a further preferred embodiment, the invention provides a system according to the invention wherein at least part of said space heat exchanger is provided with floor heating pipes encased by a thick high thermal mass preferably) concrete floor to allow daily peak shaving of the electrical grid, which is the use of stored heat (especially produced by using electricity when demand (and/or price) is low) to boost the supply at peak periods and reduce the output level required at those times. Such a thick, high thermal mass, floor is also advantageous to use in seasonal peak shaving wherein the system directs heat generated by the thermal solar collectors straight to the floor heating system to heat the floor for example in spring or autumn and the heat pump can be deactivated and bypassed until more heat is required in winter.

In a further preferred embodiment, the invention provides a system according to the invention provided with a heat recovery system. A heat recovery system (also called HRV or MVHR) works via a heat recovery ventilation unit which is usually located in the attic, roof space or plant room of a building. Heat recovery systems work by using the valuable warm air or water in a property and use it in a positive way.

Figure legends

Figure 1 A

Actual measurements of a system according to the invention located at a private home at N.52.12172, E.6.823148.

The dotted horizontal line at 10 is the theoretical 10C earth temperature. The area, above the "0" line is ~ 14.000 kWh/year which the Sun donated in the years 2016 - 2019.

The area, below the "0" line is ~ 20.500 kWh/year which the HP extracted in the years 2016 - 2019.

The sinus-like lines indicate that the storage (GHE) temperatures of the years 2016 - 2019 varied between 6 to 17C, through which years the temperatures of the GHE never were subzero. These temperature-recordings (waves) confirm that the annual GHE temperature cycle can be reliably used to build on for future results, as confirmed in the table below. These also confirm that the system can be run essentially brine free without risks on freezing events. The earth donated from underneath ~ 6.500 kWh heat/year during the period that the groundnet pipes were less than 10 C. from Jan. to April. Data from years 2109-2022 are given in the table below. Clearly, extreme freezing winter temperatures such as recorded in 2021 are well handled by the EH-system of the invention. Again, GHE in 2021 never reached subzero, well demonstrating the lack of requirements for glycol or any other anti-freezing agents that other SAHP-systems have.

Figure 1 B

Typical HP-characteristics.

Heat pump heating results increase with initial temperature of the source medium (top).

Heat pump's electricity requirements (working costs) are NOT depended on temperature of the source medium (middle). Increasing the temperature of the source medium results in higher kWh yield, and a higher COP (coefficient of performance), without increasing costs (bottom).

Figure 2

Solar radiation kWh yield / m2 at Sun Intensity on 2-7-2018 and 16 & 14 July, morning (left), and afternoon (right), respectively. This picture shows the Flat plate Sun Water Collector maximum performances on a hot and sunny day, the variable radiation intensities, and the ratio of kWh yield during daytime. Typically, generating energy is most efficient for heating the groundnet, followed by direct heating of the floor of the house. Use of solar of DHW as third most efficient, but still beats voltaic energy production.

Figure 3

An overview of present alternatives. The ground heat storage in the EH CV System is the most important advantage, second is the 20% direct solar heating to the house, also it is CO2 starkly reduced, with an annual cost lower than the present gas systems or HP + vertical borehole systems.

Heat Production HR Gas Heat Pump EH CV System kWh/y Energy Used 1.3000 2.800 1.500 Cost / Year 100% 156% 86%

CO2 Emission 29% 24% 10%

Electric Grid

Strengthening required. - 166% 0%

Figure 4

Flow diagram of a system and components according to the invention.

System components.

EH CV System sections:

1: Pump (Pl), Sun Collector (FPC), Drain back tank (DBT), Heat Exchanger (HE1).

2: Pump (P2), Heat Exchanger (HE1), 3-way valve (VI), Groundnet (GN) or House direct heating.

3 + 4: Pump (P3), Heat Pomp (HP), Pump (P4), 3-way valve (V2), to (HH) or Boiler (DHW).

5: House Heating system (HH): consists basically off. Floor Heating (FIH) + (WTW + HE2) heat exchangers, air to air + water to air.

6: (WTW) balanced mechanical ventilating heat recuperating system + (HE2) Heat Exchanger water to air for heating and / or cooling.

7: Cooling Pump (P5), 3-way valve (V3) from Groundnet to Floor and HE2 Cooling, water flow direction is then reversed.

8: Controller with many sensors, not shown.

9: HeaderTank (HT).

EH CV System Pipes:

Relative cold - (6 C. - 25 C.)

Relative warm (25 C. , 35 C. and 60 C. only for DHW)

EH CV System components descriptions:

Controller with many sensors, not shown.

(DBT) = Drain back tank

(DHW) - Boiler

(FIH) = Floor Heating

(HE1) water to water, (HE2) water to air = Heat Exchangers

(HT) = Header Tank (HP) = Heat Pomp

(Pl), (P2), (P3), (P4), (P5) = Pumps water:

(VI), (V2), (V3) = 3-way Valves

(WTW) = WTW, Balanced fresh air heat recuperating ventilation system.

Figure 5

Calculation of benefits of using a heat pump system with groundnet energy storage according to the invention (right-hand) compared with proposed benefits of an energy system without groundnet energy storage, as projected by the municipality of Haaksbergen (the Netherlands) in 2021, regarding the energy system requirements for up to 2030. The shortfall is 35% less, 1115 instead of 1724 MWh

The imbalance in the electrical grid is much smaller allowing a large reduction in grid congestion. The EV CV system incorporates a large 1000 liter domestic hot water tank in this large house with a small RVS stainless steel heat exchanger hanging in the top.

The advantage of the large domestic hot water tank lies in reducing the frequency with which the heat pump needs to supply the domestic hot water tank, avoiding the inefficient start up cycle and extending the life of the heat pump. The controller activating the hot water supply once per day at 6 in the morning and runs less that % an hour without any extra start or stops, or if there is a demand for hot water and contained temperature drops below 45°C. The small RVS heat exchanger in the top of the domestic hot water tank contains a limited water volume, ensuring regular usage, preventing any bacterial accumulation. The water in the domestic hot water tank is stored at 50°C instead of the typical 60°C. This saves a considerable amount of annual energy consumption.

Detailed description.

All current heating and cooling systems are made to satisfy the present (acute) requirements of homes. Here an embodiment of the system of the invention is described under the name of EH CV System (ElderinksHave Central Heating System). The EH CV System (ElderinksHave Central Heating System) is a complete and proven heating, cooling, and ventilation system, built from off-the-shelf reliable components such as, solar collectors, a heat pump, thick floor heating and heat recovery ventilation optimally, managed by a Controller.

What can the EH CV System deliver for consumers: 50% energy consumption reduction

Annual heating costs below the level of the past gas heating systems

50% lower CO2 emissions, environmentally friendly

Electricity demand spread, preventing peak loads on the grid

Significant reduction in grid reinforcement costs

The EH Home Heating and Cooling System consists of 7 main groups of components.

1. Solar flat plate collectors on the roof, Drain back tank, Heat exchanger and pump Pl.

2. Heat pump, 2 water pumps, 3-way valve, feeding the thick floor heating or Domestic Hot Water tank.

HRV (Heat Recovery Ventilation) + heating/cooling Ground Floor, Bathroom, and the upper floor.

4. Summer cooling pump and valve.

5. Thick floor heating system.

6. Ground net heat + buffer system with connections

7. Controller that automatically controls and optimizes all these systems.

The EH CV System has been improved over the last 12 years to outperform all other present systems.

For typical performance characteristics see also Figure 1 A and B, 2, 3 and 5, and tables 2 and 3, and others herein. It may comprise parts or a whole of an entire system, comprised of many well-known components working together in various configurations, based upon the annual heating, cooling, and ventilation requirements of modern homes, and deliver what is acutely required at minimum cost, CO2 emissions and in great comfort, all collected from the (summer) sun. At present Water solar flat plate collectors are mainly used in hot water systems, which is rather inefficient. The efficiency of Voltaic solar panels is even worse. The EH CV system transfers 80% of the total annual kWh output from water collectors into the ground net. If there is sufficient solar radiation, about 20% of the time, mainly in spring and autumn, the water collectors output is used for direct thick floor heating. Even on overcast and rainy days the solar collectors contribute significantly to the overall kWh energy into the ground net.

How it started. In 2009 we expected to get a building permit for a house in the country at ElderinksHave (EH). To get a gas pipe connection to the location would cost € 80.000. As a pensioned engineer with experience using water solar collectors, it seemed worthwhile to try using the sun as a cost-effective main heat source. The sun delivers 9.000 times more energy to our planet as all 7 billion inhabitant's use! This raises the question as to why do we hardly use it? We asked ourselves the question: Storing heat from summer, to use in winter, how can that be done? We came up with the idea to store the summer solar heat into the wet soil underground, as energy storing is still a problem for electricity, and use the stored heat to let the heat pump work at higher source medium temperatures in winter by reusing the stored summer heat. As can be observed from figure 1 B (actual measurements), where heat pump heating results increase with initial temperature of the source medium, heat pump's electricity requirements (working costs) are NOT depended on temperature of the source medium, indicating that increasing the temperature of the source medium results in higher kWh yield, without increasing costs.

A general description of our home located at N.52.12172, E.6.823148. It is a 3-story building, build in 2010, 1359 m3, 529 m2 heated, is well insulated and has large 3-layer glazing. Garage, underground 378 m3, 126 m2 well ventilated, not heated. Annual heat consumption central heating 19.000 kWh, Domestic Hot Water (DHW) 2.400 kWh. In principle, there is too little sun in winter compared to what is required. There is a great deficit from Nov. to April. This "hole" can be filled using a Heat Pump (HP) system as provided herein. Both buildings use the same horizontal ground net with each a heat pump and are CO2 neutral. Flat Plate Solar Collectors 31 m2 yield 16,000 kWh/y at 0% CO2 emission. There is also an apartment building and storage space (190 m2458 m3) provided with voltaic panels 68m2, yielding 11,000 kWh/y and 44t CO2 saved.

Running the flat plate collectors

Pumps Pl and P2 are activated when a sensor at the top of the rooftop collector indicates a temperature 15°C higher than C6 in the ground net. After filling the collectors, the speed of the pump Pl is controlled to keep a 10°C difference. In other systems, this difference is usually a Dt of 20°C meaning the pump runs slower to reduce electrical consumption. The EH CV System uses a Dt of ~ 10°C, which uses more electricity for faster pump speed, but greatly improves collected kWh output. When high enough kWh output is available, it switches the water flow from the collectors through to the thick floor heating, without the use of the HP, it is the cheapest way to heat a house. It is switched off when the kWh output is too low and the heat generated flows again into the ground net. When the system is not active, the pumps shut down, water returns to the drain back tank, thus ensuring the system will not be affected by frost. This system also prevents boiling due to sudden town power failure.

The EH CV system uses a simple 1 speed Water-to-Water heat pump. This type of heat pump will produce approximately 4 kWh of heat for 1 kWh of electricity when using the usual inlet source temperature of - 2C of a deep drill well during the heating season. A COP of 4 (Coefficient of Performance) producing 9.5 kWh from a 10 kWh unit.The source medium for EH CV System's heat pump from the ground net is between +8°C and +18°C, the output of the 10 kWh heat pump is boosted to an annual average of 12-15 kWh with a consistent power consumption of 2.2 kW. The EH CV system controller regulates the speed of the 2 water pumps, ensuring a flow of source medium at Dt 4°C and Dt 10°C to the heat pump output side. This regulation is crucial because at a higher source temperature, both the source and central heating water pumps need to move significantly more water, to allowing the heat pump to operate at peak efficiency regardless of the season. COPs of up to 8.8 are regularly observed at these temperatures.

HRV (Heat Recovery Ventilation) + heating/cooling Ground Floor, Bathroom, and the upper floor.

The HRV system facilitates air exchange throughout the entire house, ensuring that the CO2 levels are maintained between 400 and 750 ppm. Heat recovery involves transferring the extracted heat from the stale indoor air of the entire house to warm up the incoming air from outside. The incoming air is passed through a filter to remove any particles such as pollen before being circulated. In each room there is an air entrance and a gap under each door that allows to be drawn back into the HRV. Floor heating in bedrooms reacts too slowly to be practical for the varied use at different times of the day/night, such as children doing homework or home office tasks. Assuming the downstairs temperature (controlled by the thermostat) is set at 20°C, which is maintained by the thick floor heating, the HRV system continuously extracts air at approximately 19°C and delivers to the hall upstairs, with an efficiency of about 90%, this results in a continuous input of air at around 17°C into the bedrooms on the upper floor. This setup ensures excellent ventilation and maintains a comfortable bedroom temperature with closed windows year-round. Heating/cooling can be individually adjusted in all bedrooms with a switch to tell the controller to adjust the energy sent into that room if required. Stove top fumes are drawn through the extractor and passed through a carbon filter, not ejected outside. When a toilet light is turned on, a signal is sent to the controller to begin suction from the toilet bowl, this removes the need to have an always open window in the toilet. Both systems dramatically reduce wasted heat in the winter. When the outside air is above 23°C the exterior air intake is shut off by the controller, to not further heat the home.

Summer cooling pump and valve.

The Thick floor heating, HRV, and upper floor heating system can be used in the summer to cool the interior of the home, without the excessive energy cost and discomfort of traditional air conditioning, generating no noise or drafts. Using only a small pump and valve. The controller automatically activates a valve and pump when the temperature reaches a certain level, starting flow of cool water stored in the ground net buffer into the house heating system. This cool water decreases the ambient temperature in the interior.

To prevent the pump from seizing due to inactivity, the controller activates it for one minute each week.

Thick floor heating system.

A modern home is built with floor heating. Radiators need to run at 60°C to be effective. Heat pumps are not efficient at 60°C. The EH CV system uses a 'Thick' floor heating system, placing the heating pipes in the centre of the concrete floor, rather than directly underneath the tiles surface. The EH system controller can switch off the heat pump off during peak hours. The heat buffering capacity of the thick floor heating system ensures that the interior temperature will remain comfortable. Traditional gas-powered homes save energy costs by turning of the heating when not needed. In a well-insulated home, a consistent temperature can be maintained economically.

EH CV System HP electrical consumption is not needed during peak hours, reducing the need for grid reinforcement. EH CV System HP has extra capacity to store extra heat during off peak hours eliminating many starts and stops of the heat pump - extending the heat pump life. Existing heat pump systems are designed with minimal investment and capacity, leading them to have to run continuously during cold periods. These existing systems will contribute to the overloading the grid in winter.

Ground net heat + buffer system with connections

In 2009, at EH, we installed 20 pipes of 35mm HDPE 100 SDR 9, each 100 meters in length, buried at a depth of 2 meters in wet sandy soil at 1.5-meter intervals. These pipes covered a ground surface of 3,000 m2 and were connected to manifolds on both ends.

Later was determined that 10 pipes, placed 3 meters apart, could effectively handle the required heat input and extraction of 15 kWh. The source medium for the EH CV ground net system is tap water, there is no risk of ground water contamination or pollution.

All present systems depend on freezing to secure sufficient kWh capacity in winter needing an antifreeze mix in their heat source, with realistic danger of ground water contamination and pollution.

The Controller that automatically controls and optimizes all these systems.

The central hub of the "EH CV System" is the controller. Its physical hardware and software work together to enable the system's different parts to collaborate effectively, ensuring maximum efficiency and comfort. The EH CV System controller regulates for the whole house a constant and comfortable temperature and takes care that no energy is wasted. In addition to running the necessary programs for heating and cooling, the off-the-shelf controller gathers data. This information is used to optimize and provide data on performance and cost. It controls the following functions:

1. Maximizing solar reception and utilization for:

- Ground net storage (6 - 20°C)

- Direct floor heating (25 - 35°C)

2. Optimizing usage based on users' minute-by-minute demand.

3. Regulating the overall heating and cooling of the entire house.

4. Managing ventilation and CO2 control within the system. 5. Regulating the heat pump efficiency related to the ground net temperature of the source medium.

6. Recording the daily, weekly, and annual totals for all integrated systems.

7. The ability to manage and bill a communally used ground net system

The controller used in the EH CV System is the freely programmable universal controller UVR16x2 manufactured by Technische Alternative RT GmbH.

Specifications:

16 inputs:

PT1000, KTY (lkQ, 2kQ), PT100, PT500, NilOOOTKSOOO, NilOOO, NTC, room sensor, radiation sensor, humidity sensor, rain sensor, max. pulse 10 Hz, voltage up to 3.3V, resistance 1- lOOkQ, digital, Inputs 7, 8: 2 x 0-10V, 1 x 4-20mA

Inputs 15, 16: 2 x pulse 20 Hzl

16 outputs:

11 relay outputs 5 multi-function outputs, optionally 0-10V, PWM, (potential free) relay output via relay module 24 V output

The UVR16x2 controller features 16 sensor inputs that can connect to temperature sensors, other sensors, and switches. More sensors can be added using a CAN bus.

Controller Program

The device can be programmed directly via the touchscreen interface, or with a suite of software from the manufacturer called TAPPS2. TAPPS2 provides a graphical interface which allows the user to create a program in the form of a flow chart and vector diagram, which can be exported and installed on any compatible device.

Management & Information

The controller functions as a standalone web server, and when connected to the internet provides a management and control interface which can be accessed via a web browser or mobile device. This control panel allows the user to see minute by minute figures from each sensor, to monitor in real time every aspect of the system, as well as remote management and adjustment of the programmed parameters. This technical description relates to this home, but the system components can be scaled up or down, to be utilized e.g., for a whole street full of houses to get similar benefits. After much R&D and improvements, an EH CV System as described herein has now become a reliable system for heating, cooling and ventilating homes, offices, and buildings, widely applicable and documented with digitally generated operating figures since 2010. The later addition in 2014 of PV panels on the apartment have made these buildings more than 100% CO2 neutral.

An overview of present alternatives and comparison with a system according to the invention is given in figure 3. 1 Flat plate thermal hot water collectors.

10 Flat plate Sun Water Collectors on the house, 31 m2, collecting 16.000 kWh heat / year. To achieve maximum efficiency of the annual sun radiation, also under cloudy conditions most of the time the collected energy is transmitted through the heat exchanger to the horizontal groundnet storage. Pump Pl is speed controlled by 2, PT 1.000 temperature sensors, , who signal to the controller and direct the pump to maintain DT of preferably around 5C in the Sun Water Collectors. (See also figure 2, 3 and 4).

Average Radiation

Comparison of energy yield of solar versus voltaic located at N.52.12172, E.6.823148, each facing south under an angle of 36 degrees.

Through R&D and many trials we established how to get the optimum heat yield. At maximum sun input the water flow reaches 2.000 litres / hour, reducing to 300 litres / hour at minimum radiation input. The pump Pl electricity consumption averages better than 1/100 of the kWh heat yield. About 95% efficiency if discarded through the heat exchanger with counter current exchange to the groundnet by pump P2 into the ground storage at 11C to 25C. If discharged through valves KI and K3, it is transferred directly to the floor heating up to 35C, efficiency is reduced by about 30%, but it is the cheapest way to heat the house at less than € 0,04/kWh (2021 pricing is herein used). Also pump P2 is speed controlled by C2a and C2b to maintain a DT of about 10C. If used for DHW supply, the yield would only be about 35% and only at 40% of the days. Locally we have 60% cloudy conditions and that would often mean a cold shower. For this reason, EH CV System, no longer uses collectors directly for DHW, instead it uses the HP. As the horizontal groundnet storage temperature typically remains year-round between 6C - 20C, a very high HP energy yield is realized. This is also the range within which most HP will perform without trouble. The drain back tank is in the house and holds the water from the collectors when the pump Pl stops. No frost problems in the collectors and no boiling or overheating problems if the electricity fails, and finally, no risks on brine polluting the location.

R&D with Vacuum pipe collectors:

After someone started living year-round in the apartment upstairs in the shed, we expanded the water sun collectors, to cope with the added winter heat requirements. The collected heat / year / m2 is about the same. The heat collecting characteristics are somewhat different, much slower in reaction. Water flow resistance is much higher, which means more electricity consumption for the circulation pump. They are more expensive, take far more time to install and are a difficult job on the roof. No drain back possibility, this means: Risk of boiling or freezing when electricity fails, the system and (outside) piping needs insulation and heating to prevent freezing in winter. In essence, FPC perform best.

In 2014 we installed on the shed PV panels to produce electricity without CO2. Investment of € 12.000 for 11.000 kWh/y at € 0,20 / kWh, means ROI in 5,5 years.

2 Groundnet and heat storage system.

Deep borehole or a horizontal groundnet? In the Netherlands at present the depth well bored holes are used 95% of the cases. The disadvantages are: The bore hole goes through many layers of groundwater, risking groundwater pollution. Antifreeze is necessary. Far more expensive as a horizontal ground net. Practically no heat storage capacity. Brabant starts to recognize the danger of the deep drilled holes for the clean drinking water supply of this presently often used system. At EH in 2009 we laid 20 pipes, 35 mm HDPE 100 SDR 9 of 100-meter length, or similar, at a depth of 2 meters in the sandy soil at 1.5-meter centre distances, all connected to manifolds on both ends (3.000 m2 ground surface). R&D revealed that 10 pipes, at 3m apart, is sufficient to cope with the required heat input and extraction of 15 kWh, while giving enough space to accommodate 24.000 kWh/y storage required around these pipes to store the needed energy in the wet sandy soil to cope for the next winter period. Critical for the ground storage system is that the groundnet pipes can transmit the maximum input and output heat transfer to the soil (15 kWh at EH) and that the surrounding ground can store the quantity of heat (24.000 kWh at EH) for % a year. The temperature range of the groundnet storage system ranges from 6C-20C and is the EH CV System Inlet temperature of the source medium for the Heat Pump. This is what keeps the efficiency of the HP, COP above the 5. At this temperature range we can use standard water without antifreeze, avoid cost and pollution. The relative dry earth above the ground water level works like a blanket to prevent heat losses. The quantities are measured by volume sensors and associated temperature sensors PT 1000 and calculated by the controller. There are several ways to arrange the groundnet pipe system to accommodate it and its functions, so that it will fit under the homes, gardens, and street to serve many homes in a street simultaneously. E.g., by increasing the depth of the horizontal groundnet pipes the heat storage capacity can be increased. By using the turbo pipe 32mm or 42mm HDPE100 SDR17, or similar, less pipes are required to transfer the amount of heat. 3 The Heat Pump (HP)

There are mainly 2 types of HP's, "air to water" and "water to water".

The investment cost of air to water is lower, but the electrical consumption is higher, particularly under cold winter circumstances. Most present homes using a deep borehole for a water-to-water HP will attain the inlet source temperature of the Source Medium of just below zero C. during the heating season. A standard HP produces 4 kWh heat out of 1 kWh electricity. The EH CV horizontal ground storage system produces an average of 12 C. Inlet Temperature of the Source Medium for the HP. The EH CV System standard HP produces about 6 kWh heat out of 1 kWh electricity. A very nice improvement of at least 35% efficiency. However, this also requires a greater volume of the Source Medium and CH (Central Heating) water output. To adapt to these requirements the EH CV System computer controls the input pump speed P3 to maintain DT 4 C and the output pump P4 at DT 10 C to minimize electrical consumption and optimize the HP compressor efficiency. The EH CV System HP produces about 20.500 kWh/y of heat for heating out of the ground storage, the HP Compressor uses about 3.400 kWh of electricity. At € 0.20 / kWh = € 700 / year, not very much for such a large home.

4 Domestic Hot Water in the EH CV System is produced by the Heat pump.

The EH CV System uses a large boiler vessel with (dead) water to store the energy for daily consumption. On the outlet side of the HP is a 3-way valve (K2), controlled by the controller to direct the HP Hot water once a day to the boiler controlled by a temperature sensor. The EH CV System reduces the starts and stops of the Heat pump by using a large boiler vessel, avoiding many inefficient warming up periods and to extend HP life. Inside the top of this boiler vessel is a small powerful stainless steel heat exchanger fed by town water. This heat exchanger contains a small volume of water, which is frequently used and therefore not influenced by bacteria. Therefore, we only heat the boiler vessel to 50C instead of the usual 60C, which saves a fair amount of energy. There is plenty of over-capacity of the EH CV System HP to produce the DHW, instead of a lot of extra investment and roof space otherwise required for solar collectors.

5 Thick Floor heating system At EH we use a Thick Floor heating system with the floor heating pipes typically located deeper in the floor, such as in the middle of the concrete floor, instead of the pipes directly under the floor tiles. In present homes we change the temperatures day / night or at home / out to work to save energy, which can easily be accomplished with gas heaters. A modern well insulated home with a HP should preferably be kept at one comfortable temperature, because the energy losses are less than the extra strain to raise the temperature again. Most present HP systems are calculated sparingly for minimum investment and capacity, so that they will have to run continuously during cold periods. That quantity of HP electricity used in the wintertime generally causes problems for the electrical infrastructure, causing peaks in power transport over the grid. The EH Thick Floor heating system accommodates 8 hours of heat capacity and allows for peak shaving. The home heating comfort is not impaired by switching off the EH CV System HP between 17 - 21:00, to avoid over-utilization of the present electrical system capacity. This means the EH CV System HP electrical consumption does not have to be added to the "top use hours" (often from 17 - 21:00), but it can be spread over the "low use hours" the rest of the day and night, (see CO2 reduction and energy transition advantages below).

6 WTW (warmte-terug-winning) in Dutch, means "(home ventilation) heat recovery system".

A balanced, insertion and extraction of fresh air into each room, with ventilation control to maintain the CO2 values between 400 - 750 ppm. Floor heating in bedrooms may for some be not practical because one cannot cool down the room fast for bedtime. The EH CV WTW is special, because we added a heating unit to the WTW for the upstairs room heating. This heating unit is a highly efficient "low water temperature" to "air" heat exchanger. This accommodates that the bedrooms also can be used for children's schoolwork or as home office all year round. It is 20 cm thick and can be mounted to the ceiling of the upstairs bathroom or against a wall vertically to include an air moistening device. Each room has its own vent input opening, and each upstairs bedroom has also a switch to tell the controller to start the process to send extra heat into that room. Centralized air extraction, upstairs near the ceiling, from each room through a slot under each door. If e.g., the living room temperature thermostat is set at 20 C. that temperature is achieved by the floor heating system, the centralized air extraction upstairs will extract about 19 C. The WTW heat exchanger efficiency is about 90%. which means the incoming fresh air into the bedrooms will be about 17C. An excellent sleeping temperature. Kitchen vapours absorbed by a carbon filter above the stove, not through the wall to the outside. When anybody goes to the toilet, the light will be turned on - this will signal the controller to switch valves to start suction out of the toilet bowl, keeping the surrounding fresh, and both measures saving a lot of energy waste in winter.

7 Summer cooling, the living room floor and upstairs in all bedrooms.

In summer, the groundnet storage water temperature is typically on average at around 14 - 16 C. This medium is pumped through the ground floor and the WTW unit upstairs. It will achieve a comfortable inside temperature around 24C when outside temperatures reach 30C. All that EH CV System uses, is a small pump and 3-way valve (Figure 4, V3 and PS) to reroute the groundnet water. It brings 2.500 kWh/y comfort for a few € on electricity, without drafts and expense of an air conditioner. The acquired heat is stored into the ground storage for use next winter.

8 EH CV System Controller

The facilitate smooth and economical running heating and cooling system, minimizing energy consumption and CO2 emission, a controller may be used which may use measuring points at desired locations in the basic Flow diagram (figure 4). It may control optimum sun reception and utilization to for example: Groundnet storage 6 - 20C Direct floor heating 25 - 35C

Optimum utilization for user demands per minute

Total house heating

Boiler water temperature

Ventilation and CO2 control,

The HP-efficiency in relation to groundnet temperature of the source medium Recording the daily totals of all systems.

It can be used for annual heat in/output quantity to be shared by a common Groundnet, and to utilize minimum electrical tariffs if available, and can be provided with many more functions, if required. The EH CV System controller regulates for the whole house a constant and comfortable temperature and takes care that no energy is wasted while being as economical as possible. The total EH CV System preferably uses tap water as Source Medium, the best medium to transfer the energy, no additives or antifreeze. This means, cheap and never any risk of pollution. It runs at only 1 atm, with low temperatures, inexpensive piping is used. Only piping from the HP to the boiler needs to withstand 60 C.

Comparisons Costs of heating a house with the different Systems what does it cost : €/kWh % WarmtePompWeetjes.NL Elect, from the grid € 0.200 265% invest. Years Depr/Y Yield./yenerg./y Cost/y HR Gas Installation € 0.075 100% 1,500 15 € 100 12,981 € 878 € 978

HP Air € 0.108 143% 10,500 15 € 700 12,981 € 700 € 1,400

HP 4 Borehole € 0.118 157% 17,000 15 / 30 € 917 12,981 € 614 € 1,531

Elderinkshave (EH System) / kwh Totaal

Water Coll.+grndnet € 0.000 26% 7,000 30 € 233 15,100 € 62 € 295 € 0.020

Solar Floor heating * € 0.036 47% 2,596 € 0.036

Solar DHW € 0.065 87% € 0.065

HP DHW EH € 0.114 151% € 0.094 € 0.114

HP Central Heating EH € 0.067 88% 6,600 30 € 220 10,385 € 268 € 488 € 0.047 € 0.067

CV EH Solar *4 HP * € 0.060 80% 12,981

9 CO2 reduction and advantages for the energy transition

More Government Network savings using the EH CV System: Another very important and cost saving feature of the EH CV System is that 20.500 kWh/y of energy from this one home is not shuttled back and forwards through the government electrical NETwork system, commonly called grid. A substantial CO2 reduction and energy transition effects can be realized by 2050 using the EH CV System for the build (Power & Light) environment. This could amount to something like 50% of the 42 Mt/y of CO2 emission of 2012 during the energy transition towards 2050 (in the Netherlands), see also figure 5 and table below. In that figure, the left graph is the regional energy transition 2030 planning, showing that Voltaic panels on homes or in fields do not contribute at the right time to balance the governmental electric energy system. From the total annual values (green), I translated this into monthly situations for the concept 2021 of Haaksbergen (left diagram) and what, if the EH CV System were used instead (right diagram). On the right top it shows the amount of energy not transferred back and forth through the government electrical NETwork system. That amount of electricity is in winter not needed for heating by the EH CV System HP and reduces the Central heating amounts under the "0" line and reduces the MWh shortages. Basically, no Voltaic panels on homes or in fields are required and the electricity deficit in winter is drastically reduced in 2030 due to the free Summer Sun Energy and the electricity savings of the EH CV System. Plan OverMorgen To-2050 TJ Elect. Heat Storage Fields Amount € Investment m2

Solar Parks 336 37% 0% 34 342473 € 94180108 582204

EH CV System 904 50% 50% Tota € 107574485 626938

This would amount to a saving of € 93.560.623 of investments in Haaksbergen.

Instead of using sun panels producing only when the sun is shining, applying windmills producing day and night electricity to be able to spread production for use in an type of EH CV HP home systems according to the invention results in a considerable saving in Twente for the Government electrical infrastructure improvement. We just need to double the number of windmills as of 2030 to become CO2 neutral. According to the present planning we would require the number of windmills in 2050 if the electricity savings of the EH CV System would be utilized.

Summary conclusions

The EH CV System (ElderinksHave Central Heating System) has several distinct elements that may work together in various combinations to contribute to the CO2 neutrality. These are: Flat plate thermal hot water collectors allowing to store energy in water or soil and not in electricity. Groundnet and heat storage system, reducing grid congestion and energy costs. The Heat Pump (HP). Domestic Hot Water in the EH CV System may be produced by the Heat pump. Thick Floor heating system allows peak shaving, reducing grid congestion and energy costs. Warmte terug winning (WTW) in Dutch, means "home ventilation heat recovery system". Summer cooling, the living room floor and upstairs in all bedrooms. EH CV System Controller reducing grid congestion and energy costs. CO2 reduction and advantages for the energy transition for the government. Adapted laws and regulations may sometimes be beneficial.

Hybrid systems are only temporary solutions to use less gas. CO2 emission improvement are doubtful. Many costs, little financial benefit. If the gas supply shuts off, you have to start over. Air heat pumps are most used today because it is the cheapest in terms of investment and therefore the easiest to sell. They are however the worst solution in terms of energy consumption costs per year. Again, they have only a CO2 emission improvement of 2%, that does not help our environmental problem. Heat pump with deep drilling. In terms of energy consumption costs per year are still very expensive. CO2 emission improvement 5%, that does not solve our environmental problem either. Risk: In the event of leakage from the depth bore, ground (drinking) water will be contaminated by antifreeze.

EH CV System energy consumption costs halved per year. Total costs per year below the level of the HR Gas Installation. CO2 emissions are reduced by 66% when using gray electricity. Due to the lower consumption, fewer wind turbines are needed to supply enough CO2 neutral electricity. Gigantic savings on grid investments (annual electricity costs account). Isn't it time the government will select the issuance of building permits based on annual CO2 emissions?

Claims

Claims

1 An essentially brine-free system equipped for heating at least one enclosed space, said system comprising at least a ground source heat pump (HP) to transfer energy from a low temperature ground heat source to an elevated temperature space heat source, said system comprising a means to control the system, said system combined with

A) a solar thermal collector (SC) system provided with a drain back tank,

B) at least one closed loop ground heat exchanger (GHE) herein also identified as groundnet (GN),

C) at least one floor heat exchanger (FIH)

D) at least one pump Pl allowing temperature-controlled fluid flow through said solar thermal collector (SC) to said ground heat exchanger (CHE) or to said floor heat exchanger (FIH).

2 The system according to claim 1 wherein said pump Pl is directed by said means to control to maintain a temperature difference (AT) of at most 15 to 2 degrees Celsius, preferably 12-6, more preferably at around 9-11 degrees Celsius between outlet fluid and inlet fluid of said solar thermal collector (SC), when outlet T > inlet T, allowing sensible heat transfer from solar thermal collector (SC) to ground heat exchanger (CHE) or to floor heat exchanger (FIH).

3 The system according to claim 1 or 2 additionally provided with a heat exchanger (HE1) capable of transferring heat obtained by said thermal collector to said ground heat exchanger (GHE) or said floor heat exchanger (FIH) when said heat-pump (HP) is not required to provide said space with heat, allowing storing said heat generated by said collector in said closed loop ground heat exchanger or in said floor heat exchanger (FIH).

4 The system according to any of claims 1-3 additionally provided with at least one three-way valve VI allowing direct routing of heat generated by said collector to said space or to said groundnet.

5 The system according to any of claims 1-4 wherein said collector is a flat plate collector (FPC).

6 The system according to any of claims 1-4 wherein said pump Pl is directed to maintain a temperature difference (AT) of at most 12 to 2 degrees Celsius (Co) between outlet fluid and inlet fluid of said collector, when outlet T > inlet T.

7 A system according to any of claims 1-5 provided with at least one additional pump P2 allowing temperature-controlled fluid flow through said closed loop ground heat exchanger. 8 The system according to any of claims 1-7 wherein said additional pump P2 is directed to maintain a temperature difference (AT) of at most 20 to 2 degrees Celsius between inlet fluid and outlet fluid of said closed loop ground heat exchanger, when inlet T > outlet T.

9 The system according to any of claims 1- 8 wherein said at least one additional pump P2 is directed by a heat-pump system controller equipped with sufficient temperature sensors capable of registering temperature of incoming fluid and outgoing fluid of said closed loop ground heat exchanger.

10 The system according to any of claims 1-9 wherein pipes comprising said closed loop essentially horizontal ground heat exchanger are essentially installed at a distance of at least 1.5, preferably 2, more preferably at least 3 meters distance from each other.

11 The system according to any of claims 1-10 provided with at least one additional pump P3 allowing temperature-controlled fluid flow from said closed loop ground heat exchanger to said heat-pump system (HP) is directed to maintain a temperature difference (AT) of 2-6 degrees, preferably 3-5 degrees Kelvin between source input and output of said heat pump (HP).

12 The system according to any of claims 1-11 provided with at least one additional pump P4 and three-way valve V2 allowing temperature-controlled fluid flow from said heatpump system (HP) to said space heat exchanger is directed to maintain a temperature difference (AT) of 8-12 Kelvin between space input and output of said HP.

13 The system according to any one of claims 1-12 provided with at least one additional pump P4 and additional 3-way-valve V2 allowing allowing temperature-controlled fluid flow from said heat-pump system (HP) to a Domestic Hot Water (DHW) tank.

14 The system according to any one of claims 1-13 provided with at least one additional pump P5 and additional 3-way-valve allowing fluid flow from said closed loop ground heat exchanger to said space heat exchanger under conditions wherein cooling of said space is desired.

15 The system according to any one of claims 1-13 wherein at least part of said floor heat exchanger is provided with floor heating pipes encased by a floor of sufficient thermal mass to allow for peak shaving.

16 The system according to any one of claims 1-14 wherein said floor is made of concrete.