NL2016365B1

NL2016365B1 - System of a building for heat and power generation

Info

Publication number: NL2016365B1
Application number: NL2016365A
Authority: NL
Inventors: Jan Joseph Jansen Sander
Original assignee: Mauri Invest Company B V
Priority date: 2016-03-04
Filing date: 2016-03-04
Publication date: 2017-09-19

Abstract

The present disclosure relates to a system of a building. The building comprises at least two individual accommodations, such as apartments (3 – 6) and public space(s) (2), each of which has heat exchangers and an independent electricity meter with connected electrical circuitry. The system of the disclosure comprises a co-generating heat and power generator (9, 20). Further, the system comprises a heat circuit (10) connecting the generator to the accommodations for heating. Finally, the system comprises an electrical circuit connecting the generator (9) to the electrical circuitry of the individual accommodations behind the meters (7) of the accommodations for power.

Description

SYSTEM OF A BUILDING FOR HEAT AND POWER GENERATION

The present disclosure relates to a system of a building for heat and power generation.

Such a system has the features of the appended independent system claim.

It is acknowledged to be commonly known that electrical energy and heat can be generated from the perspective of a single building having a single user, owner or inhabitant, even if this is a corporation. For example sun panels on building roofs are known, and co-generating heat and power generators, or combined heat and power (CHP) units or thermal power plants are being used with increasing intensity, but exclusively in the domain of big buildings, for example housing a considerable company.

It is also acknowledged to be commonly known, that a surplus of energy generated by a wind mill or solar panels can be sold to a utility grid, benefitting single users, owners or inhabitants with the means to invest in and exploit such installations.

The objective of the present disclosure is to enable inhabitants of multi-accommodation buildings to generate energy and profit there from, even though, individually, these parties do not have sufficient means to acquire the likes of wind mills and expensive solar installations or CHP units.

Herein below preferred embodiments of the present disclosure will be described by reference to the appended drawings. These preferred embodiments are by no means intended as limiting on the scope of protection for the present disclosure and should in no case be interpreted as such. In the drawings, distinct embodiments can contain the same or similar reference signs for identical or functionally similar elements, aspect or components. In the drawing:

Fig. 1 shows a schematic representation of a system in a building according to the present disclosure;

Fig. 2 shows a schematic representation of the electrical circuit of the system of Fig. 1;

Fig. 3 shows a schematic of a starter system connected to a thermal power plant or CHP and the grid;

Fig. 4 shows a summary of the control steps executed by the starter system of Fig. 3; and

Fig. 5 shows the frequency of the power output by a Variable Frequency Drive (VFD) to the generator as a function of time.

Figure 1 exemplifies a building 1, which is connected to the utility grid 13, and comprises common or public space(s) 2, and apartments 3-6. Each apartment has its own electricity meter 7 connected to the grid 13, and a fuse box 8 connected to the meter 7. Connections to different parts of the apartments 3-6 and of public space(s) 2 form outputs of the fuse boxes 8. In such domestic environments, fuse boxes are normally limited to power supply of a maximum of approximately 15A and sometimes as much as 25A in three phases. Practically all currently available thermal power plants require considerably higher current levels, in particular for start-up.

Further, building 1 has a common or joint heat circuit 10, comprising heat exchangers 11 in all of the apartments 3-6 and possibly also in the public space(s) 2 (not shown). A co-generating heat and power generator 9, which is referred to sometimes as a combined heat and power (CHP) unit or a thermal power plant, is arranged for instance in a basement of the building 1. The generator 9 may run on fossil fuel, bio fuel, gas, or any other suitable material. For start-up, the generator 9 is connected to the grid 13, possibly via an output of fuse box 8 in the common or public space(s) 2. The generator 9, after start-up, generates power for output to an electrical circuit supplying power to each of the public space(s) 2 and the apartments 3-6.

The fuse box 8 and output connections thereof for each of the public space(s) 2 and the apartments 2-6 may be referred to as electrical circuitry, to distinguish over the electrical circuit forming the output of the generator 9. The electrical circuit at the output side of the generator 9 is arranged in addition to the conduits from the grid 13 to the meters 7 and comprises a distributing controller 12, which is shown in more detail in figure 2. From the distributing controller 12 individual conduits are connected to electrical circuitry after the meters 7 in each apartment 3-6 or the public space(s) 2. These conduits are in addition to the cables split from the grid 13 to the meters 7 in the individual accommodations 3-6 and/or the public space(s) 2. This way the energy supplying companies cannot charge for energy that is locally generated and not supplied over the utility grid. Moreover, inhabitants of the accommodations or apartments can sell to the grid 13 exploiters a surplus of energy in relation to their individual accommodations, which is supplied to them from the generator 9, via their individual meters 7.

The distributing controller 12 is in principle configured to pass power supply to only one of the apartments or accommodations and the common or public space(s) at a time. However, there’s no technical impediment for supplying energy to more than one of these elements of the building 1.

The controller 12 comprises an energy meter 14, for example a MODBUS, and a control module 15, for example based on a Programmable Logic Circuit (PLC). The energy meter 14 monitors an amount of energy supplied to any connected accommodation, apartment 3 - 6 or common or public space(s) 2, and outputs a monitoring signal to the control module 15. When a target amount of energy is furnished to one of the apartments 3 - 6 or the common or public space(s) 2, the control modules adjusts the switches 16, HS to - from then on - supply energy to a next one of the apartments 3-6 and the public space(s) 2. In this way fair and equal distribution of the generated energy from the generator 9 is achieved. For instance, the control module 15 may be configured to switch accommodations for power supply, after a target amount of energy of for example 50 kWh is supplied to one thereof. Alternatively, the control module 15 could be configured for equal time switching, but - assuming a steady rate of power generation - such a strategy may result in a less objectively fair and equal distribution, for example as a result of considerations, like that an inhabitant will use more of the power from the generator 9 himself, if supplied during the early morning hours before work and/or early in the evening, when everybody is home, cooking and watching television and using electrical apparatuses like computers, and not be able to sell as much energy to the grid 13, as an inhabitant who always gets connected at 13.00 ‘o-clock in the afternoon. Switching based on distributed amounts of energy is considered more preferable.

Further, in particular in case of a thermal power plant or Combined Heat and Power (CHP) unit, power generation will increase at times of a high heat demand. A participant in the system of the present disclosure (an inhabitant of the building) who is assigned a time slot of high heat demand, would also be attributed more generated power, than another participant who is assigned a time slot with low heat demand (middle of the day or night). In any case, time division is anticipated to result in unfair distribution of generated power amongst participants / inhabitants of the building.

Settings of the control module 15 may be adaptable, potentially even remotely, for example via a network, such as the internet 16 using for example a computer 17, a mobile device like a smart phone or a tablet, et cetera. One of the inhabitants of the apartments 3-6 could be given control over the settings of the control module 15, using a program on a computer or an app on a mobile device. All of the inhabitants could be granted access rights via programs or apps to at least inspect or view amounts of energy supplied to them and to other inhabitants.

If one of the accommodations or apartments 3 - 6 is empty at any given time, the control module could be adapted to skip the empty apartment 3-6 with respect to power supply from the generator 9 thereto.

The public space(s) 2 could also benefit from the energy generated by the generator 9. Especially if there’s an uneven number of apartments 3-6, allowing the public space(s) 2 to be supplied with energy generated by the generator may be employed to ensure fair and equal distribution of the energy.

The control module 15 may be configured to open switches to a next apartment 3-6, while first keeping open supply to a previous apartment 3-6. When the next apartment is connected fully, the distributing controller closes the switches to the previous apartment. This can contribute to maintaining synchronicity with the grid 13.

The generator in the form of a thermal power plant may generate sufficient energy and warmth for an entire block of apartments 3-6 and the public space(s) 2. However, building 1 is not disconnected from the grid 13 for a number of reasons (there may be other and/or more reasons):

It is intended to sell to the grid 13 a surplus of energy, from which the inhabitants benefits, which requires some connection to the grid 13.

If at any time the energy supply to any one of the apartments 3-6 cannot meet a demand from any given connected apartment 3-6, energy from the grid can still be used to supplement supply to meet the need.

If a thermal power plant is used as the generator, it will need to be able to attract energy from the grid 13.

In the embodiment of Fig. 2, a ramping starter 18 is arranged between the distributing controller 12 and the generator 9 in the form of a thermal power plant. It is known that thermal power plants 9 attract high currents for start-up. In particular, common thermal power plants require a current of at least 100 A for start up. In a domestic environment of a public building, three phase 25A is normally the maximum of current that can be made available to a thermal power plant. Normally therefore, a thermal power plant would not be feasible without a special connection allowing it to attract such an amount of current. The ramping starter 18 obviates the need for any special connections for start-up of a thermal power plant, and allows the thermal power plant or Combined Heat and Power (CHP) unit to start-up with as little current as a maximum of 25 A or even as low as 10 A.

Figure 3 shows a generator 9 in the form of a Combined Heat and Power (CHP) unit 20 (comprising an induction generator and a combustion engine, not shown) connected to the grid 13. A starter system 19 for the CHP 20 comprises a variable frequency drive 21 and a bypass relay 22. Each of these components is connected between the grid 13 and the CHP 20, and provides an alternative connection between the grid 13 and the CHP 20. That is, the variable frequency drive 21 and bypass relay 22 are connected in parallel.

The starter system 19 also includes a controller 23. The controller 23 is in communication with the variable frequency drive 21 and the bypass relay 22, and is configured to control both these components. The controller 23 is also configured to receive input data from a grid sensor 24, which monitors the voltage and current supplied by the grid. The grid sensor 24 includes a phase locked loop to measure the phase angle of the grid voltage. The controller 23 is also configured to receive input data from a sensor (not shown) configured to measure the speed of the engine. The controller is also configured to output data concerning the operation of the CHP to a network connection (not shown). The controller also controls switch/relay 25.

The starter system 19 is not provided with heat exchangers or electrical shielding; this is not necessary, since the VFD is not in operation for a long period of time.

The heat to be removed from the system is mainly the heat lost from the bypass relay 22. In an exemplary starter system 19 for a 20 kW CHP unit, 12 W of power is dissipated in the starter system 19 during normal operation. The time for start up is so short that the components of the starter system 19 do not get hot; the temperature may rise by approximately 5 °C, but this will not have a significant effect on any of the components. The starter system 19 is large enough to dissipate the produced heat by convection from its surfaces, for example, from an aluminium casing (not shown). For comparison, a VFD with 5% losses connected to the same 20 kW CHP unit produces 1,000 W of heat that must be dissipated.

For continuous-use VFDs, dissipation of this heat is a significant design consideration.

The control steps executed by the controller 23 are shown schematically in Figure 2. When the starter system is initialised, the controller 23 performs a diagnostic of the CHP 20 and/or the starter system 19 and reports any error found. If no errors are found, the controller 23 performs a diagnostic of the grid 13, based on information from the grid sensor 24. Any errors that are found are reported. In the event that no errors are found, the controller 23 checks whether a request has been made to start up the CHP. If not, the controller 23 waits. If such a request has been made, the controller 23 initialises start up of the CHP.

Prior to initialisation of the CHP, the switch 25 is open, such that there is no connection between the grid and generator. The bypass relay 22 is also open. On initialising start up of the CHP, the controller 23 closes switch 25, thereby providing a connection from the grid 13 to the generator 20 via the variable frequency drive 21.

The controller 23 controls the variable frequency drive 21 to supply to the generator power at a lower frequency than that received from the grid, and then to increase (i.e. ramp up) the frequency to the grid frequency. The frequency of the power supplied to the generator is shown as a function of time in Figure 3. In this example the controller 23 controls the variable frequency drive 21 to initially reduce the frequency of the power received from the grid to 2 Hz. The frequency is maintained at this initial value for 1 second. Subsequently, the controller 23 controls the variable frequency drive 21 to ramp up the frequency. In this example, the frequency is ramped up from 2 Hz to 50 Hz (the grid frequency) within 2 seconds.

When the generator 20 is synchronized to the grid voltage, the controller closes the bypass relay 22 to connect the generator 20 directly to the grid 13, bypassing the variable frequency drive 21.

In this example the prime-mover for the CHP unit is an internal combustion engine and the generator start-up hence also acts to turn the engine over. After the bypass relay 22 has been closed then the generator is operated as a motor for a period of time before the internal combustion is started in order to allow the exhaust system of the engine to be ventilated. This may for example be around 10 seconds or so. After this delay the internal combustion engine is started and the CHP unit 20 then operates in a normal running mode, with the engine providing the power to turn the generator to thereby generate electricity.

By starting the CHP in this way, the inrush current drawn from the grid is limited to acceptable levels, by virtue of the provision of the VFD 21. The starter system 19 also allows the VFD to be bypassed once the generator is running, allowing direct connection between the generator and grid. The bypass relay has a significantly higher efficiency than the VFD and so by closing the bypass relay in normal operation (i.e. after start up), the total efficiency of the CHP is increased dramatically. In this way the CHP operates efficiently both during the start phase and during normal operation.

Additionally, since the VFD only operates for a short time, much less heat is generated compared to the configuration in which the VFD operates continuously whilst the CHP is operating. This means embodiments of the present invention are much more efficient compared to prior art systems, and do not require extensive heat dissipation apparatus or electrical shielding. The reduced heat load also extends the service life of the generator and starter system.

Claims

A system of a building, comprising at least two individual accommodations, such as apartments (3-6) and public space (2), each of which has heat exchangers, and an independent electricity meter with an electrical installation connected thereto, the system comprising: - a cogenerating heat and power generator (9, 20); - a heating circuit (10), which connects the heating generator to the accommodations; - an electrical circuit which connects the generator (9) for electricity to the electrical installations of the individual accommodations behind the meters (7) of the accommodations.

The system of claim 1, wherein the electrical circuit comprises a distribution control (12) for sequentially providing energy generated by the generator (9) to at least one of: the accommodations (3-6); and the public space (2).

The system of claim 2, wherein the distribution control (12) comprises an energy meter (14) and is configured to evenly distribute the energy generated by the generator (9) over the accommodations (3-6) and the public space (2), based on equal amounts of energy supplied, which are measured by the energy meter (14).

The system of claim 2 or 3, wherein the distribution control (12) comprises a programmable control module (15).

The system of claim 4, wherein the settings of the control module (15) are adjustable.

The system according to any one or more of claims 2 to 5, wherein the distribution control (12) is configured to keep an unoccupied accommodation unconnected.

The system according to any one or more of claims 2 to 6, wherein the distribution control (12) is configured to connect common or public space (2) in sequence with other accommodations.

The system according to any one or more of the preceding claims 2-7, wherein the distribution control (12) is configured to, when switching to another of the accommodations, open switches to a subsequent accommodation to be connected while initially keeping supply to a previously connected accommodation open to disconnect the previously connected accommodation after synchronization with an electricity network (13) has been stabilized.

The system according to any one or more of the preceding claims, further comprising an ascending starter (18) in conjunction with the co-generating heat and power generator (9, 20).

The system according to any one or more of the preceding claims, comprising a starter (19) with a variable frequency drive (21) and a bypass relay (22) arranged in parallel between an electricity network (13) ) and the co-generating heat and power generator (9, 20), as well as a controller (23) which controls the variable-frequency drive and (21) the bypass relay (22), the controller controlling the variable-frequency based drive (21) to supply power to the generator at a lower frequency than that supplied by the electricity grid (13) and then to increase (ie increase) the frequency to the frequency of the electricity grid in order to , when the generator is synchronized with the voltage of the electricity grid, close the bypass relay (22) to connect the generator (20) directly to the electricity grid (13) so as to variable frequency based drive (21).

The system of claim 10, further comprising an electricity grid sensor (24), comprising a phase locked loop to measure the phase angle of the electricity grid voltage.

The system according to claim 10 or 11, further comprising a controlled switch or relay (25) between the power grid (13) and the parallel circuit of the variable frequency-based drive (21) and the bypass relay (22), and below the control of the control (23).