GB2032602A

GB2032602A - Improvements in or relating to heat pumps

Info

Publication number: GB2032602A
Application number: GB7835671A
Authority: GB
Original assignee: WR HEAT PUMPS Ltd
Current assignee: WR HEAT PUMPS Ltd
Priority date: 1978-09-05
Filing date: 1978-09-05
Publication date: 1980-05-08
Also published as: GB2032602B

Abstract

A refrigeration cycle heat pump comprises an evaporator (not shown), a compressor (10) and a condenser (12) for a refrigerant medium in which the major components are immersed in a heat exchange medium from or by which useful heat is extracted. Preferably the major components comprise the compressor (10), a power unit (16), which is preferably an internal combustion engine, and the condenser coil (12). The liquid may be oil for cooling and lubricating the unit and forming the fluid for a coupling (15) between the unit and compressor. <IMAGE>

Description

SPECIFICATION Improvements in or relating to heat pumps This invention relates to improvements in or relating to heat pump systems and is particularly concerned with the improvement of the overall efficiency of such systems.

It has long been proposed to provide means for transferring heat from one medium to another in the form of a heat pump comprising a refrigeration system having a motor driven compressor to compress a suitable gas, a condenser coil to cool the compressed gas thus to transmit heat from the gas to a first medium, an evaporator in which the cooled compressed gas is allowed to expand in the process extracting heat from a second medium, before being compressed again in the compressor. Such heat pump systems per se are well established with suitable control systems to make them operative.

It is an object of the present invention to improve the efficiency of such a system.

Accordingly the present invention provides a heat pump system in which the major components at least are immersed in a heat exchange medium which forms part of the heat pump system. The heat exchange medium is preferably contained in a thermally insulated container.

Preferably the heat pump system includes an internal combustion engine, as a power source, immersed in the heat exchange medium which thus acts as a coolant for the engine. Preferably the exhaust system for the engine includes heat exchange means whereby exhaust gas heat may be given up to the heat exchange medium.

Preferably the heat exchange medium is lubricating oil and is used to lubricate at least the internal combustion engine.

Preferably the heat pump system immersed in the heat exchange medium includes at least the compressor and condenser coil of a refrigeration cycle heat pump. Preferably the compressor is driven by the engine through the intermediary of a fluid coupling, the heat exchange medium serving as the fluid for that coupling.

Preferably the system includes heat exchange means immersed in the heat exchange medium for the extraction of useful heat from the system.

In order to promote a fuller understanding of the above and other aspects of the present invention, an embodiment will now be described, by way of example only, with reference to the accompanying drawing which shows in schematic outline an embodiment of the invention.

In the embodiment of the invention shown there is provided a compressor 10 in a refrigerant gas circuit indicated generally at 11. The circuit also includes a condenser coil 12 and an evaporator coil which is not shown. The evaporator coil is positioned to extract heat from a heat bearing medium such as the atmosphere, or the ground. the condenser coil 12 is arranged to give up heat from the refrigerant gas during operation of the system to a heat exchange medium indicated at 13, which in this embodiment is oil contained in a casing 14 which encloses the embodiment of the invention.

The compressor 10 is driven by way of a coupling device indicated at 1 5 by means of an internal combustion engine 1 6. The internal combustion engine 1 6 draws air through a suitable inlet 1 7 from outside the casing 14 and the exhaust gases are led from the engine 1 6 by way of a heat exchanger 1 8 in the heat exchange medium 13, to an exhaust outlet 19 from the casing 14.

In this embodiment the internal combustion engine is arranged to run on gaseous fuel, for instance natural gas, and the outlet 1 7 embodies a suitable gas carburettor to mix the fuel gas with incoming air for combustion in the engine. It will be appreciated however that the engine 1 6 may be other forms of internal combustion engine, or indeed may be an electric motor.

A heat exchange coil 20 is also provided in the casing 14 to extract heat from the heat exchange medium 13 as a means for extracting useful heat from the pump. The heat exchange coil 20 may be filled with water or other suitable heat exchange medium with suitable pumping facilities being provided to conduct heat away from the system.

The heat exchange medium 13 is preferably oil, and oil which is suitable for lubricating the mechanism of the engine 1 6.

The coupling 1 5 between the engine 16 and the compressor 10 is preferably of a fluid flywheel type, the heat exchange medium 1 3 providing the fluid for the coupling.

While in the arrangement shown is transferred from the heat exchange medium 13 to the medium in the heat exchange coil 20, it will be appreciated that the heat exchange medium 13 itself may be pumped from the casing 14 to circulate through a heat consuming device and back to the casing 14 as a means of extracting useful heat.

Thus it can be seen that the embodiment provides a heat pump for pumping heat from the air or the ground, or other heat bearing medium, to provide a useful output of heat either in the heat exchange medium 13, or in the medium in the heat exchange coil 20. It is anticipated that the system would operate with an output temperature of some 1 600F which is particularly suitable for domestic central heating with water or oil filled radiators.

The provision of a fluid flywheel coupling between the engine 16 and the compressor 10 enables the operation of the engine 1 6 at a constant speed with the compressor speed fluctuating as load on the compressor changed. It is envisaged that it would be arranged that the normal compressor load will result in an engine output speed of some 3000 revolutions per minute with a zero degree Fahrenheit evaporation temperature corresponding to minimum slip in the fluid coupling. Maximum slip in the fluid coupling would occur at some 400F evaporation temperature. With such an arrangement a constant output may be obtained from the heat pump and the engine would have a constant load and speed and therefore requires a minimum of control equipment. Further the system would be self-compensating for different temperatures in the source heat bearing medium in contact with the evaporator.

It will be appreciated that by immersing the entire system in the heat exchange medium 13, all heat losses from various components of the system are retrieved back into the heat exchange medium 13. The casing 14 may be thermally insulated to further improve such regain of lost heat. Thus for a given quantity of fuel burnt in the engine 1 6, the entire calorific value, apart from a small amount of residual heat in the exhaust gases leaving the outlet 19, should be retained in the heat exchange medium 1 3 for extraction to useful purpose. Thus the invention provides an extremely efficient system for pumping heat from a heat bearing medium in contact with the evaporator, to be available for some useful purpose.

Claims

1. A heat pump in which the major components are immersed in a heat exchange medium which forms part of the heat pump.

2. A heat pump as claimed in Claim 1 in which the major component and the heat exchange medium are enclosed in a thermally insulated container.

3. A heat pump as claimed in Claim 1 or 2 in which said major components comprise a compressor, a power unit to drive the compressor and a condenser coil for the heat pump medium.

4. A heat pump as claimed in Claim 3 in which the power unit comprises an internal combustion engine.

5. A heat pump as claimed in Claim 4, in which an exhaust heat exchanger is provided in the exhaust system of the engine to extract heat from the exhaust gases to said heat exchange medium.

6. A heat pump as claimed in Claim 4 or 5 in which said heat exchange medium is used as a cooling medium for the engine.

7. A heat pump as claimed in Claim 4, 5 or 6, in which said heat exchange medium is used as lubricant for the engine.

8. A heat pump as claimed in any of claims 4 to 7 in which said engine is adapted to use gaseous fuel.

9. A heat pump as claimed in any of Claims 3 to 8 in which the power unit is arranged to drive the compressor through the intermediary of a fluid coupling.

1 0. A heat pump as claimed in any preceding claim in which useful heat is extracted from the pump by means of a second heat exchange medium.

11. A heat pump as claimed in Claim 10 in which a heat exchange coil is provided in the first heat exchange medium for the second heat exchange medium.

12. A heat pump as claimed in Claim 10 or 11 in which second heat exchange medium is liquid.

13. A heat pump as claimed in any one of Claims 1 to 9 in which useful heat is extracted from the pump by way of said heat exchange medium.

14. A heat pump as claimed in any one of Claims 3 to 13 in which the evaporation of the heat pump is arranged to extract heat from the ground or ambient air.

1 5. A heat pump substantially as herein described, with reference to the accompanying drawings.