GB2475693A

GB2475693A - A heat pump cabinet especially for use with small domestic houses or apartments

Info

Publication number: GB2475693A
Application number: GB0920673A
Authority: GB
Inventors: Gary Stanton Webster; Jeremy James Stanley
Original assignee: Smiths Environmental Products Ltd
Current assignee: Smiths Environmental Products Ltd
Priority date: 2009-11-26
Filing date: 2009-11-26
Publication date: 2011-06-01
Also published as: GB0920673D0; WO2011064564A3; WO2011064564A2; EP2504629A2

Abstract

The heat pump cabinet 10 comprises a housing 11 divided into upper 12 and lower 13 sections. The lower section houses a heat pump 14 adapted to provide heated water to a domestic hot water system and heated air to a forced air convection heating system. The upper section houses a fan 22, plenum 21 and at least one spigot connector 23, wherein the fan forces air through the plenum and the connector transfers air from the plenum to one or more ducts of the forced air convection heating system. The heat pump may comprise a first 15 and second 16 heat exchanger associated with the domestic hot water and forced air convection heating systems respectively. The heat pump cabinet may have a width or depth of less than 350mm, such that the cabinet may fit between upright studwork members of an internal wall construction. A heating installation including the heat pump cabinet is also claimed. The installation may include air ducts attached to the spigot connectors with steel noggins (dwangs) having apertures being installed between the studwork members to receive and direct the ducts.

Description

Heat Pump Cabinet This invention relates to a heat pump cabinet, and to a heating installation incorporating such a heat pump cabinet, for providing heating and hot water to a building.

As reserves of fossil fuels such as coal, oil and gas begin to deplete and consequently rise in price, the use of alternative energy sources for domestic heating has become more attractive. Combined with this, there is widespread public concern over climate change, which is attributed partly to carbon dioxide emissions from combustion of such fossil fuels. This has led to an increased demand both for alternative energy based domestic heating systems, and for more energy efficient systems as general public awareness of energy supply issues has increased.

However, many of the new generation of energy saving heating systems which have appeared on the market are so highly priced that it would take longer than the operating lifetime of the system for the cost savings attributable to the increased energy efficiency to equal the original purchasing cost. As such, the installation of "green" domestic heating systems has hitherto been beyond the financial reach of many consumers.

The present invention seeks to address the above issues by providing an energy efficient, fossil fuel free, domestic heating system designed specifically for use in small houses or apartments, which will be well within the financial reach of the average consumer. Because the present invention has been designed specifically for use in small houses or apartments, significant cost savings can be achieved by providing an integrated system which combines the heat source and the distribution means together "in one box", avoiding the need for multiple heat emitters such as radiators or electrically operated convector heaters to be installed around the house. It is envisaged that the purchasing cost of the domestic heating system of the present invention will be recovered through the cost savings attributable to increased energy efficiency well before the end of the system's life cycle.

The present invention further seeks to provide a heating installation which is also capable of operating in reverse mode so as to provide a cooling function, as required, to a dwelling in which it is installed. A yet further aim of the present invention is to provide an unobtrusive heating installation meeting which will be quiet to operate and which may be at least partially recessed within the structure of the building in which it is installed.

According to a first aspect of the present invention there is provided a heat pump cabinet comprising: -a housing, divided into upper and lower sections; -a heat pump located in the lower housing section, said heat pump being adapted to provide heated water to a domestic hot water system and to provide heated air to a forced-air convection heating system; -fluid connectors, adapted to transfer heated water from said heat pump to a hot water coil of an indirect domestic water storage tank, and to return cooled water from said coil to the heat pump; -a plenum located in the upper housing section; -an electrically driven fan located in the upper housing section and adapted to drive or draw heated air through said plenum; and -one or more spigot connectors adapted to transfer heated air from the plenum to one or more ducts of a forced-air convection heating system.

The heat pump cabinet of the present invention thus combines the heat source, in the form of the heat pump, and the distribution means, in the form of the electrically driven fan, together in a single integrated unit. This enables significant savings to be made both in terms of cost and the space occupied by the heating system, thus making it ideal for installation in small houses and apartments.

As will be understood, a heat pump in its simplest form comprises a closed circuit around which a refrigerant fluid is circulated. The circuit includes an electrically operated compressor which pressurises the fluid, in its gaseous form, thus causing the refrigerant gas to heat up. The hot pressurised gas is then circulated through a condenser, within which it condenses to a liquid, though still under high pressure. This causes the condenser itself to generate heat, which may then be dissipated to its surroundings. From the condenser, the high pressure liquid refrigerant is circulated to an expansion valve, which has the effect of lowering the pressure of the liquid refrigerant so as to promote evaporation.

The low pressure liquid refrigerant is then circulated to an evaporator, where it evaporates into a gas, absorbing heat from the evaporator's surroundings as it does so. The gaseous refrigerant then returns to the compressor, and the cycle repeats.

Because heat is transferred from the condenser to the surroundings, and from the surroundings to the evaporator, both of these components may be termed a "heat exchanger", and this term will be used herein. It should be understood that, for heat pump systems adapted to operate interchangeably between "normal" and "reverse" modes so as to provide both heating and cooling functions, the same component may operate interchangeably as both an evaporator and a condenser.

In the present invention, the components of the integral heat pump housed within the heat pump cabinet can be taken to comprise one or more heat exchangers (whether operating as evaporators or condensers), and the expansion valve. It is intended however that the compressor should be located externally of the building in which the heat pump cabinet is installed, in order to keep the noise level generated by the heat pump to a minimum, within the building. At least one heat exchanger -usually configured to operate as an evaporator in order to absorb heat from the surroundings -is also required to be located externally of the building, or at least to be in communication with ambient air from outside the building (assuming the heat pump is an air source heat pump).

The heat pump preferably comprises a first heat exchanger adapted to provide heated water for the domestic hot water system, and a second heat exchanger adapted to provide heated air for the forced-air convection heating system. It is envisaged that the first heat exchanger will be configured always to operate as a condenser in order to supply heat to the domestic hot water system.

The second heat exchanger will be configured normally to operate as a condenser in order to supply heat to the forced-air convection heating system. In preferred embodiments of the present invention however, the second heat exchanger will be configured to operate interchangeably as a condenser -as described above -and in "reverse" mode as an evaporator in order to provide cool air to the forced-air convection system.

The first heat exchanger is preferably located in the lower housing section, with the fluid connectors being adapted to transfer heated water from said first heat exchanger to a hot water coil of an indirect domestic water storage tank, and to return cooled water from said coil to the first heat exchanger. The second heat exchanger is preferably located in the upper housing section, with the electrically driven fan being arranged to drive or draw air over said second heat exchanger, thereby to heat the air.

The second heat exchanger is preferably located substantially within the plenum. Most preferably, the second heat exchanger is located substantially at the top of the plenum, and the electrically driven fan is located at or adjacent the base of the plenum and is arranged to drive air over the second heat exchanger, thereby to heat the air.

As noted above, in preferred embodiments of the present invention, the second heat exchanger is adapted also to operate in reverse mode -i.e. as an evaporator -thereby to enable cool air to be driven or drawn through the plenum, such that the forced-air convection system can be used to supply cool air to a building in which the heat pump cabinet is installed.

It is envisaged that in such embodiments, the heat pump may be adapted such that the first heat exchanger operates as a condenser and the second heat exchanger effectively operates as an evaporator in the same refrigeration circuit, such that heat recovered from the air in the plenum is transferred to the domestic hot water system.

The heat pump cabinet according to the present invention preferably has a width and/or depth of less than 350mm (14 inches). This dimension is the standard spacing between upright studwork members in internal wall construction in the UK housing industry. As such, this enables the heat pump cabinet to be at least partially recessed within an internal wall of the apartment or small house in which it is installed, thus providing a further space-saving benefit.

In order that the present invention may meet it aims of providing a low cost heating installation, the heat pump is preferably an air source heat pump. The heat pump may alternatively be a ground source heat pump -which are generally more efficient at delivering recovered energy to a building -however, these tend to be more expensive than air source heat pumps and therefore do not lend themselves so well to meeting the aims of the present invention.

The air source heat pumps preferred for use in the present invention are designed to operate at a co-efficient of performance (COP) of approximately 3:1.

This means that for approximately every unit of energy consumed (from the mains electricity supply required to operate the heat pump), the heat pump will deliver 3 units of energy to the building in the form of heat. This level of performance can be maintained even when the ambient temperature is as low as 5°C -the temperature of an average winter's day in the UK.

According to a second aspect of the present invention there is provided a heating installation comprising: -a heat pump cabinet as hereinbefore described; -an indirect domestic water storage tank having a hot water coil in communication with the fluid connectors of said heat pump cabinet; -one or more air ducts, each in communication at one end thereof with a spigot connector of the heat pump cabinet, and at the other end thereof with a diffuser nozzle adapted to be located in a ceiling vent of a building in which the heating installation is installed.

In preferred embodiment of heating installation according to the second aspect of the present invention, the compressor associated with the heat pump is located externally of the building in which the heating installation is installed. This serves to maintain noise levels within the building at a low level, enabling the heat pump cabinet to operate quietly. As noted above, at least one heat exchanger associated with the heat pump -normally configured to operate as an evaporator -will also necessarily be located externally of the building, or at least be in communication with ambient air from outside the building (assuming the heat pump is an air source heat pump).

In order to facilitate the recessing of the heat pump cabinet within an internal stud wall of a building and the connection of the one or more spigot connectors on the heat pump cabinet with the one or more air ducts of the forced-air convection system, the heating installation preferably further comprises one or more specially designed steel noggings having apertures therein adapted to receive said one or more air ducts. Each nogging is adapted to fit between standard 350mm (14 inch) spaced upright studwork members in an internal stud wall.

In order that the present invention may be more clearly understood, a preferred embodiment thereof will now be described in detail, though only by way of example, with reference to the accompanying drawings in which: Figure 1 is a front, cross-sectional view of a heat pump cabinet according to the first aspect of the present invention; Figure 2 is a side cross-sectional view of the upper section of the heat pump cabinet of Figure 1; and Figure 3 is an illustrative representation of a heating installation according to the second aspect of the present invention, incorporating the heat pump cabinet of Figure 1.

Referring first to Figure 1, there is shown a heat pump cabinet 10, according to a first aspect of the present invention. The cabinet 10 has a housing 11, divided into an upper section 12 and a lower section 13.

The lower section 13 houses an integral air source heat pump 14 having a first heat exchanger 15 and a second heat exchanger 16 associated therewith -the second heat exchanger 16 being housed in the upper section 12 of the housing 11. The first and second heat exchangers 15, 16 are each normally configured to operate as condensers, so as to supply heat, respectively, to a domestic hot water system 31 and a forced-air convection system 32, as will be described in more detail below with reference to Figure 3.

The evaporation part of the refrigeration cycle is performed by a further heat exchanger 17 which is configured normally to operate as an evaporator. The further heat exchanger 17 must be in communication with ambient air located externally of the building in which the heat pump cabinet 1 0 is installed, in order to recover heat therefrom, though the heat exchanger 1 7 itself need not necessarily be located externally of the building. As shown in Figure 1, the further heat exchanger 17 of the preferred embodiment is provided with fluid connectors 18 either to deliver ambient air directly to the heat exchanger 17, or more practically to deliver an intermediary fluid such as water -which will be in thermal communication with the ambient air externally of the building. As will be described in more detail below with reference to Figure 3, a compressor associated with the heat pump 14 is also located externally of the building.

The first heat exchanger 15 is also provided with fluid connectors 19, adapted to deliver heated water from said first heat exchanger 15 to the domestic hot water system 31 of the building in which the heat pump cabinet is installed, as will again be described in more detail below with reference to Figure 3.

Referring now simultaneously to Figures 1 and 2, the upper section 12 of the housing 11 houses a plenum 21, at the base of which is located an electrically driven fan 22, and in the upper part of which is located the second heat exchanger 16. The fan 22 is adapted to draw in air from the room in which the heat pump cabinet 10 is located, and drive it into and through the plenum 21. As the air passes through the upper part of the plenum 21 it passes over the second heat exchanger 16 and heated air is thus generated. The heated air exits the heat pump cabinet 10 via spigot connectors 23, from where it enters the forced-air convection system 32, as will be again described in more detail below with reference to Figure 3.

Referring again to Figure 1, the heat pump 10 is provided with control means 24, adapted to switch the operation of the second heat exchanger 16 between "normal" and "reverse" modes -that is, to switch the operation of the second heat exchanger 16 between condenser and evaporator -depending on whether the user requires the forced-air convection system 32 to supply heated or cooled air. Operation of the control means 24 may also be regulated thermostatically.

When the second heat exchanger 16 is operating in reverse mode, the control means 24 may be adapted to configure the heat pump 14 such that the first and second heat exchangers 15, 16 operate, respectively, as condenser and evaporator in the same refrigeration circuit. This enables heat recovered by the second heat exchanger 16 from air in the plenum 21 to be supplied, via the first heat exchanger 15 to the domestic hot water system 31. Alternatively, where no hot water is desired, or where the temperature of water in the domestic hot water system 31 has already reached the desired level, the control means 24 may be adapted to configure the heat pump 14 such that the further heat exchanger 17 also operates in reverse mode -i.e. as a condenser.

Referring now to Figure 3, there is shown a heating installation, generally indicated 30, according to a second aspect of the present invention, and incorporating the heat pump cabinet 10 of the first aspect, as described above with reference to Figures 1 and 2. As can be seen, the heat pump cabinet 10 is connected to a domestic hot water system, generally indicated 31, and a forced-air convection heating and cooling system, generally indicated 32.

Connection to the domestic hot water system 31 is effected via the fluid connectors 19 for the first heat exchanger 15, to which are connected flow and return pipes, 33, 34 for a hot water coil 35 of an indirect domestic water storage tank 36. Hot water pipes 37 then draw off hot water from the storage tank 36 for domestic hot water appliances (taps, shower, bath etc.) 38 as required.

The heat pump cabinet 10 is shown in Figure 3 installed in a building and partially recessed between two adjacent upright studwork members 39 of an internal stud wall. Connection to the forced-air convection system 32 is effected via the spigot connectors 23 at the top of the plenum 21, to each of which is connected a length of flexible air duct tubing 41, adapted to pass up between the studwork members 39 into a ceiling void 42 above a suspended ceiling 43. To support the flexible tubing 41 between the studwork members 39, a special steel nogging 44 is provided (also shown in plan view in Figure 3 for illustrative -11 -purposes), having apertures 45 formed therein to receive the flexible tubing 41.

The nogging 44 is adapted to fit between the adjacent studwork members 39.

Each length of flexible tubing 41 terminates at a ceiling vent 45, and is provided with a diffuser nozzle 46, through which the heated or cooled air generated in the plenum 21 is delivered to the building, as indicated by arrows a.

As discussed above with reference to Figure 1, the further heat exchanger 17 of the heat pump 14 is required to be in fluid communication with ambient air located externally of the building. As can be seen in Figure 3, this is achieved by means of a radiator unit 47 which is in fluid communication with the further heat exchanger 17 via fluid connectors 18. A fan 48 is provided to drive ambient air over the water-filled pipes of the radiator unit 47 so as to transfer heat from the ambient air to the further heat exchanger 17. The compressor for the heat pump 14 is also located externally of the building in order to reduce noise levels within the building, and may conveniently be housed within the radiator unit 47.

Claims

Claims 1. A heat pump cabinet comprising: -a housing, divided into upper and lower sections; -a heat pump located in the lower housing section, said heat pump being adapted to provide heated water to a domestic hot water system and to provide heated air to a forced-air convection heating system; -fluid connectors, adapted to transfer heated water from said heat pump to a hot water coil of an indirect domestic water storage tank, and to return cooled water from said coil to the heat pump; -a plenum located in the upper housing section; -an electrically driven fan located in the upper housing section and adapted to drive or draw heated air through said plenum; and -one or more spigot connectors adapted to transfer heated air from the plenum to one or more ducts of a forced-air convection heating system.
2. A heat pump cabinet as claimed in claim 1, wherein the heat pump comprises a first heat exchanger adapted to provide heated water for a domestic hot water system, and a second heat exchanger adapted to provide heated air to a forced-air convection heating system.
3. A heat pump cabinet as claimed in claim 2, wherein the first heat exchanger is located in the lower housing section, and wherein the fluid connectors are adapted to transfer heated water from said first heat exchanger to a hot water coil of an indirect domestic water storage tank, and to return cooled water from said coil to said first heat exchanger.
4. A heat pump cabinet as claimed in claim 2 or claim 3, wherein the second heat exchanger is located in the upper housing section, and wherein the electrically driven fan is arranged to drive or draw air over said second heat exchanger, thereby to heat said air.
5. A heat pump cabinet as claimed in claim 4, wherein the second heat exchanger is located substantially within the plenum.
6. A heat pump cabinet as claimed in claim 5, wherein the second heat exchanger is located substantially at the top of the plenum, and the electrically driven fan is located at or adjacent the base of the plenum and is arranged to drive air over said second heat exchanger, thereby to heat said air.
7. A heat pump cabinet as claimed in any of claims 2 to 6, wherein said second heat exchanger is adapted also to operate in reverse mode, thereby to enable cool air to be driven or drawn through the plenum, such that said forced-air convection system can be used to supply cool air to a building in which said heat pump cabinet is installed.
8. A heat pump cabinet as claimed in any of the preceding claims, having a width and/or depth of less than 350mm (14 inches).
9. A heat pump cabinet as claimed in any of the preceding claims, wherein the heat pump is an air source heat pump.
10. A heat pump cabinet as claimed in any of claims 1 to 8, wherein the heat pump is a ground source heat pump.
11. A heat pump cabinet as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.
12. A heating installation comprising: -a heat pump cabinet as claimed in any of the preceding claims; -an indirect domestic water storage tank having a hot water coil in communication with the fluid connectors of said heat pump cabinet; -one or more air ducts, each in communication at one end thereof with a spigot connector of the heat pump cabinet, and at the other end thereof with a diffuser nozzle adapted to be located in a ceiling vent of a building in which the heating installation is installed.
13. A heating installation as claimed in claim 12, wherein the heat pump further comprises a compressor, located externally of the building in which the heating installation is installed.
14. A heating installation as claimed in claim 12 or claim 13, wherein the heat pump further comprises an external heat exchanger, in communication with ambient air located externally of the building in which the heating installation is installed.
15. A heating installation as claimed in any of claims 12 to 14, further comprising one or more steel noggings having apertures therein adapted to receive said one or more air ducts.
16. A heating installation as claimed in claim 12 and substantially as hereinbefore described with reference to the accompanying drawings.