WO1990002300A1

WO1990002300A1 - Heat pump for heating or cooling confined spaces, and also for heating tap water

Info

Publication number: WO1990002300A1
Application number: PCT/SE1989/000440
Authority: WO
Inventors: Alf Karlsson
Original assignee: Thermia Ab
Priority date: 1988-08-22
Filing date: 1989-08-22
Publication date: 1990-03-08
Also published as: SE8802951L; SE8802951D0; SE464667B

Abstract

A heat pump for heating or cooling dwelling houses or like confined spaces includes a refrigerant circuit which comprises a compressor (1), a first heat-exchanger (7) thermally connected to a heat source, a second heat-exchanger (4) thermally connected to a fan system, a third heat-exchanger (2) thermally connected to a tap hot-water system (11, VV), an expansion valve (5) and a two-position refrigerant flow reversal valve (3). The valve (3) is operative to reverse the flow sequence between the various units in the refrigerant circuit, depending on whether the heat pump is to produce heat or cold. Irrespective of whether the heat pump is intended to deliver heat or cold, it can be caused, at the same time, to produce hot tap water or to maintain the temperature of the water without needing to interrupt prevailing heating or cooling of the rooms or spaces concerned. This is made possible by heating the tap water directly in the third heat-exchanger (2) and by causing the tap water to pass through control apparatus in the form of a circulation pump (8) and a valve (9), or a shunt (10) which bypasses the valve, during its passage from the third heat-exchanger (2) to the tap water network (VV).

Description

HEAT PUMP FOR HEATING OR COOLING CONFINED SPACES, AND ALSO FOR HEATING TAP WATER

TECHNICAL FIELD

The present invention relates to a heat pump for heating or cooling dwelling houses and other confined spaces in which such requirements prevail, and also for heating tap water. The heat pump includes a compressor, a first heat-exchanger connected thermally to a heat source, a second heat-exchanger connected thermally to a fan system, a third heat-exchanger connected thermally to a tap water system, an expansion valve, and a two-position flow-reversing switch. When the switch is set to a first of its two positions, the heating position, refrigerant flowing from the compressor will pass through the heat- exchanger, the second heat-exchanger, the expansion valve, the first heat-exchanger and from there back to the compressor. When the switch is in the second of its two positions, the cold position, refrigerant flowing from the compressor will pass through the third heat- exchanger, the first heat-exchanger, the expansion valve, the second heat-exchanger and back to the com¬ pressor.

BACKGROUND PRIOR ART

Such heat-pump systems are used in air conditioning or climatic systems for heating living spaces or corresponding spaces in winter and cooling said spaces in summer, and are also used to heat tap water the whole year round. These known systems, however, present difficulties when wishing to heat confined spaces in winter while providing hot tap water at the same time. Normally, such systems are designed either to produce heat for room-heating purposes or heat for producing hot tap water. Since it can be presumed that the structural elements from which the building concerned is built will normally have stored therein sufficient heat to allow the space-heating facility of the system to be inactive over a not too long period, without experiencing discom¬ fort, the tap-water heating facility of the system is normally given priority. Notwithstanding this, a drop in temperature in part of the building served by the system can well be experienced as unpleasant, as a result of the manner in which the supply of heat is divided bet¬ ween the various rooms or spaces concerned, or due to the fact that some rooms border on warm internal walls while others border on cold outer walls, etc.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a heat pump by means of which the heat available can be distri- buted between the confined spaces of a building and the hot tap-water system and be used to heat said spaces and said tap water in parallel, with the aid of simple means and with the least possible heat losses. This object is achieved in accordance with the invention with a heat pump have the characteristic features set forth in the following claims.

BRIEF DESCRIPTION OF THE DRAWING

An exemplifying embodiment of an inventive heat pump will now be described in more detail, with reference to the accompanying drawing, the single figure of which is a block schematic of an inventive heat pump.

DESCRIPTION OF AN EXEMPLIFYING EMBODIMENT The illustrated exemplifying heat pump includes a first heat-exchanger or evaporator 7, one side of which is connected to an evaporator coil 13 which is intended to be placed, for instance, in a hole in the ground, for the purpose of utilizing ground heat, and in which an aqueous solution of lowered freezing point can be cir¬ culated with the aid of a circulation pump 12. The other side of the heat-exchanger is connected to a refrigerant circuit, comprising a compressor 1, a second heat- exchanger 4 which is thermally connected to a fan system intended for blowing hot or cold air into the spaces to be heated or cooled respectively, a third heat-exchanger 2 which is connected to a tap hot water system, a con- tainer 11 of which is illustrated in the drawing, a circulation pump 8, a valve 9 and a shunt 10 which bypasses the valve. The refrigerant circuit further includes an expansion valve 5, a drying filter 6, and a two-position refrigerant-flow reversal valve 3. The refrigerant is preferably halogen, for instance one of the refrigerant types retailed under the name Freon. When the valve 3 is set to the first of its two posi¬ tions, the heating position, as illustrated in the drawing, refrigerant flowing from the compressor 1 passes through the heat-exchanger 2, the second heat- exchanger 4, the expansion valve 5, the filter 6, the first heat-exchanger 7 and back to the compressor 1. When the valve 3 is set to the second of its two posi¬ tions, the cooling position, the input and output lines extend parallel with one another, instead of crossing one another, and the refrigerant flowing from the com¬ pressor 1 will pass through the third heat-exchanger 2, the first heat-exchanger 7, the filter 6, the expansion valve 5, the second heat-exchanger 4 and back to the compressor 1. Although not shown, the heat pump includes control equipment, inter alia for starting and stopping the circulation pumps 8, 12 and the fan system co-acting with the heat-exchanger 4, for opening and closing the valve 9, and for adjusting the setting of the expansion valve 5. The heat pump can be set into four different operational modes by means of the control equipment, namely;

1. A heating mode in which the reversal valve 3 is set to its heating position and the electric current for driving the circulation pump 8 and opening the valve 9 is disconnected. In this setting, the refrigerant heated by compression in the compressor 1 passes to the third heat-exchanger 2 and from there to the second heat- exchanger 4, in which the heat contained by the refri¬ gerant is transferred to the air blown by the fan system through the heat-exchanger and out into the spaces to be heated. The refrigerant then passes through the expan¬ sion valve 5 and the drying filter 6, to the first heat- exchanger 7, where it takes-up heat from the liquid circulating in the pipe coil 13, prior to being again compressed in the compressor 1.

2. A heating and hot-water mode. In this mode of the heat pump, the system settings are the same as those described under 1 above, but with the difference that electric current is now supplied to the pump 8 and the valve 9. When the tap water needs to be heated, a fact which is established by a thermostat (not shown) con- nected to the water container 11, the circulation pump 8 is started up. In response hereto, water is taken from the container 11 or, if water is tapped from the system, from a cold water connection KV, and is caused to flow through and be heated in the third heat-exchanger 2. If the fan of the fan system co-operating with the second heat-exchanger 4 is in operation for room heating pur¬ poses, the production of hot water is restricted by holding the valve 9 closed, wherewith water will circu¬ late solely through the narrow-bore and flow-restricted shunt 10. As a result of this arrangement, only a part of the heat available will be used to produce hot water and consequently the room-heating and hot-water producing facilities can be in operation at one and the same time. When the rooms or building has been heated to a pre-set temperature, the fan cooperating with the second heat-exchanger 4 will stop and the pressure in the outlet of the heat pump will increase, this increase pressure being detected by a pressure switch (not shown) mounted in the line between the compressor 1 and the third heat-exchanger 2. This pressure switch functions to open the valve 9 and therewith make the whole of the power delivered by the heat pump available for producing hot water. The heat pump will continue to work until the pre-set tap-water temperature has been reached. The shunt arrangement affords the additional advantage that as soon as the heat pump is started for room-heating purposes, maintenance-heating of the tap water in the container 11 is effected at the same time, since a certain amount of tap water is circulated through the heat-exchanger 2, the stationary pump 8 and the shunt 10 by a so-called ther osyphon effect.

3. An Air-conditioning and hot-water mode. In this mode • of the heat pump, the reversal valve 3 is set to its cold position. The refrigerant heated by compression in the compressor 1 will then pass through the third- exchanger 2 and from there to the first heat-exchanger 7, which in this mode of the heat pump functions as a condenser and thus conducts the heat to the liquid present in the pipe coil 13. The refrigerant then passes through the drying filter 6, the expansion valve 5 to the second heat-exchanger 4 cooperating with the fan system, and is vapourized in the heat-exchanger 4 while taking-up heat from the fan-air passing from the heat- exchanger 4. If the tap water requires heating, the circulation pump 8 is started and the valve 9 is opened, while at the same time shutting down the circulation pump 12 in the pipe coil 13, wherewith the hole of the thermal power is taken-out through the third heat- exchanger 2. When the tap water has been heated to the pre-set temperature, the pump 12 is again started while throttling the circulation of hot tap-water through the heat-exchanger 2 at the same time.

4. A hot water mode. In this mode of the heat pump, the reversal valve 3 is set to its heating position and the fan system is switched off. The heat pump is started-up when the need for hot water arises, and simultaneously starts the circulation pump 8. When the temperature in the pipe located between the compressor 1 and the third heat-exchanger 2 has reached a pre-set value, the valvj 9 is opened and the all of the system power available is used to produce hot tap water. The heat pump shuts down, when the hot tap water has reached a pre-set temperature.

Thus, the heat pump can be set to a mode in which it will function solely to heat a room or like confined space, to a mode in which it functions solely to heat tap water, or to a mode in which tap water is heated in combination with producing hot or cold air. It will be understood that the heat pump can be modified within the scope of the inventive concept. For instance, the heat pump can be complemented with an additional heat- exchanger for connection to radiators located in rooms or like confined spaces which only require to be heated and not to be air conditioned. Furthermore, the shunt 10 can incorporate a valve for the purpose of controlling the flow through said shunt and for closing the shunt when the heat pump is set to mode 1 above. Instead of providing a shunt, the valve 9 can be constructed so as not to close fully, but to permit adjustments to be made to the flow of hot tap water there through.

Claims

CLAIM

1. A heat pump for heating or cooling dwelling houses and other confined spaces in which such requirements prevail, and also for heating tap water, said heat pump including a refrigerant circuit comprising a compressor (1), a first heat-exchanger (7) connected to a heat source, a second heat-exchanger (4) connected to a fan system, a third heat-exchanger (2) connected to a hot- water system (11), an expansion valve (5) and a two- position refrigerant-flow reversal valve (3) which when set to a first of said positions, the heating position, is operative to cause refrigerant flowing from the compressor (1) to pass through the third heat-exchanger (2), the second heat-exchanger (4), the expansion valve (5), the first heat-exchanger (7) and back to the com¬ pressor (1), and which when set to the second of its two positions, the cooling position, is operative to cause refrigerant flowing from the compressor to pass through the third heat-exchanger (2), the first heat-exchanger (7), the expansion valve (5), the second heat-exchanger (4) and back to the compressor (1), characterised in that tap water to be heated, taken from a cold water connection (KV) or a water container (11),passes through the third heat-exchanger (2), from where the tap water is passed by means of a circulation pump (8) and a valve (9) to a tap water network (W) for storage of unused water in the container (11), from which the water is caused to recycle, for maintenance heating purposes, by a thermosyphon effect through the third heat-exchanger (2) and through the now stationary circulation pump (8) , back to the container (11), said circulation being made possible by a shunt (10) which bypasses the valve (9) or by shunt means incorporated in the valve itself.