SE445773B - Heat pump device for temperature regulation and ventilation of a locale - Google Patents

Abstract

Heat pump device for temperature regulation and ventilation of a locale. The device comprises a cooling medium circuit (1), whose condenser (H1) is in thermal-transmitting contact with the airflow in a supply air unit (2) and whose evaporator (H2) is in thermal-transmitting contact with the extract air from the locale. The condenser (H1) is situated in a flow device (16) with bypass line (20) that is housed in the supply air unit (2). A separate damper is used to divide the total supply air between the condenser (H1) and the bypass line (20) so that the condenser temperature is maintained at the desired level so the heat pump can work with great efficiency under various operation conditions.<IMAGE>

Description

lO ¿. 4 of 20 25 30 8302895-1 2 before the condenser battery. However, this results in poorer heat economy, as the condenser then constantly has to work at a higher temperature level.

It is also possible to control the capacity of the heat pump compressor within certain limits, but regardless of how this is done, e.g. by relieving the compressor's suction valves, the heat factor drops significantly at low loads, which is why the overall efficiency is also low with such a control method.

The object of the invention is to obviate these disadvantages and thus to regulate the heat transfer from the refrigerant circuit to the supply air in such a way that the supply air does not have to be mixed with return air and the refrigerant circuit can nevertheless operate with maximum efficiency within a fairly large temperature range. . This object is achieved in that the first heat exchanger battery, which normally functions as a condenser, is arranged in a flow-through device, which is provided with a bypass, in the supply air unit (either next to the fan or in the supply air duct system). In this case, means are arranged to distribute this total flow between the condenser battery and the bypass for a given total flow in the air duct in dependence on the temperature of the refrigerant in the condenser battery or a quantity which varies with it. In this way, the heat transfer capacity of the refrigerant circuit can be adapted to the currently prevailing need while maintaining a high efficiency. The supply air fan can operate with a constant supply air flow, and no mixing of return air is necessary.

For example, by means of dampers, the air flow through the condenser / heat exchanger battery can be controlled so that the condenser is kept at the desired, relatively high temperature level, e.g. 35 ° C. When the supply air (normal outdoor air) is only to be heated moderately, e.g. from + 10 ° C to + 21 ° C, a certain part of the total supply air flow can be led next to the condenser / heat exchanger battery through the bypass. With greater heating needs, an increasing proportion of the total supply air flow can be conducted through the condenser / heat exchanger battery, while an increasingly smaller part can be conducted via 10 20 25 30 Lu IJ! 8302895-1 bypass.

To enable a satisfactory temperature control, the condenser battery (the first heat exchanger battery) is suitably divided into at least two condenser parts arranged in each duct branch parallel to the bypass, said means (eg dampers) being arranged to distribute the air flow in resp. channel branch in such a way that each condenser part maintains the desired temperature. In this way, maximum efficiency can be maintained within a larger temperature range, as the distribution possibilities become greater. For further expansion of the control range, at least two compressors can be gradually connected in the refrigerant circuit, either in parallel with each other in the same circuit or in separate refrigerant subcircuits with associated condenser part, throttle valve and evaporator part.

By dividing the refrigerant circuit into several parallel sub-circuits, the control accuracy can also be increased. Suitably a separate sensor, e.g. a pressure or a temperature sensor, arranged in resp. refrigerant sub-circuit for regulation of resp. condenser temperature, while another separate sensor, e.g. a flow sensor, a differential pressure sensor or an absolute pressure sensor, is arranged in the supply air duct for constant maintenance of the total supply air flow by controlling a damper in the bypass.

For uniform division of the control area, the condenser parts are suitably dimensioned in such a way that a stepwise increasing heat transfer to the supply air is obtained by connecting one or more condenser parts in different combinations.

The heat pump device according to the invention normally has its second heat exchanger battery arranged in an exhaust air unit next to the exhaust air fan or in the exhaust air duct system).

When the room requires ventilation, the supply of the supply air unit is connected to the outdoor air, while the exhaust air unit 10 15 20 25 30 35 8302895-1 ° 4 sucks in exhaust air from the room. In this case, heat is thus pumped from the exhaust air to the outdoor air / supply air by means of the heat pump device, at the same time as good air exchange is achieved in the room. The connection of the compressor or compressors (and / or condenser part) of the refrigerant circuit can be made depending on the exhaust air temperature, but the regulation can also be carried out depending on the supply air temperature, the air temperature in the room and / or the outdoor temperature. When the need for ventilation is reduced or completely absent, the supply air unit can instead suck in return air (circulating air) from the room, while the inlet air unit's inlet is made to communicate with the outdoor air. This can be applied when the activity ceases in the premises, e.g. during nights and weekends. This significantly improves the heat economy, since no outdoor air needs to be heated. Instead, the required heat is taken from the outdoor air in the second heat exchanger battery acting as a condenser, whereby the outdoor air is blown out via the exhaust air unit with an even lower temperature.

Suitably, the heat pump pump device is arranged so that the direction of circulation in the refrigerant circuit or circuits is reversible, e.g. with the help of one in resp. circuit breaker valve, so that the first heat exchanger battery acts as an evaporator and the second heat exchanger battery acts as a condenser, whereby the supply air to the room can be cooled, which may be relevant when the outdoor temperature is high, e.g. in summer, or if heavy heat-generating processes occur in the room. In this case, it is provided resp. circuit with a throttle valve and an associated, parallel-connected non-return valve next to each heat exchanger battery, so that the refrigerant circuit can work in both directions.

The heat pump device can in principle absorb the required heat from any heat source other than the exhaust air or the outdoor air, namely from any heat-emitting medium, e.g. flowing water or a circulating liquid that absorbs solar heat, ground heat, heat from sewage systems or heat from sewage systems or heat stored in a storage container or other heat storage.

The invention is explained in more detail below with reference to the accompanying drawings, which illustrate a practical embodiment.

Fig. 1 shows a schematic diagram of a heat pump device connected between a supply air unit and an exhaust air unit; Fig. 2 schematically shows three refrigerant sub-circuits included in the heat pump device. Fig. 1 shows diagrammatically in the form of a central block 1 a refrigerant circuit operating as a heat pump (shown in Fig. 2) which is connected between a supply air unit with associated duct system 2 and an exhaust air unit with associated duct system 3. The supply air duct system 2 opens into one or several supply air devices (not shown) in a room which is to be heated and ventilated, and which may consist of e.g. a larger workshop hall or a building with several room units.

The operation of the heat pump 1, like the supply air and exhaust air duct systems 2,3, is controlled by a control center, which is schematically indicated as a block RC in the drawing.

The supply air duct system 2 comprises two air inlets, namely an inlet 4 for outdoor air U and an inlet 5 for return or circulation air C from the room in question. Invid resp. inlet is a damper arranged, namely an outdoor air damper 6, which is operated by an actuator 7 controlled from the control center RC, and a return air damper 8, which is controlled by an actuator 9 also controlled from the control center RC. Downstream of the return air damper 8 a temperature sensor T1 is arranged. The inlets 4 and 5 are connected to a common supply air duct 10, which in the direction of flow is provided with a filter 11, a flow-through device 16 consisting of three mutually parallel duct branches 17, 18, 19 and a parallel bypass 20 ( wherein the duct branches l7, l8, l9 are connected to a first heat exchanger battery H1, of which more below), a supply air fan Z1 and a reheating battery 22 (which is controlled by the control center RC via a switch motor 23, which operates a valve 24, of the supply air temperature sensed by means of a temperature sensor T3). From the outlet of the supply air duct, the supply air T flows out to the room.

The exhaust air duct system 3 shown on the right in Fig. 1 comprises two inlets, namely an inlet 25 for exhaust air E and an inlet 26 for outdoor air U. In the case of resp. Inlet is a damper arranged, namely an exhaust air damper 27, which is operated by a control motor 28 controlled from the control center RC, and an outdoor air damper 29, which is operated by a control motor 30, which is likewise controlled from the control center RC. Downstream of the exhaust air damper 27, a temperature sensor T4 is arranged. The inlets 25 and 26 are connected to a common exhaust air duct 31, which in the flow direction is provided with an exhaust air fan 32, a filter 33 and a second heat exchanger battery H2.

In addition to the temperature sensors specified above, an outdoor temperature sensor T5 and at least one local temperature sensor T6 can be connected to the RC control center. In addition, a differential pressure sensor DP is arranged to sense the pressure difference between two points A and B upstream resp. downstream of the flow-through device 16 for keeping the total supply air flow constant by operating a damper in the bypass 20 by means of an actuating motor SP1.

The heat pump 1 itself and the associated heat exchangers H1 and H2 are shown in more detail in Fig. 2. The heat pump consists of three parallel, closed refrigerant subcircuits 34a, 34b, 34c, each with its own compressor 35a, 35b, 35c, reversing valve 36a, 36b, 36c, pressure sensor 37a, 37b, 37c, first heat exchanger part Hla, Hlb, Hlc (normally functioning as a condenser) with connected non-return valve 38a, 38b, 38c and throttle valve 39a, 39b, 39c 10 l 10 20 30 8302895-1 (parallel to the respective non-return valve), second heat exchanger part H2a, H2b, H2c (normally acting as evaporator) with connected non-return valve 40a, 40b, 40c (opposite or non-return valve 38a, 38b, 38c) and throttle valve 4la, 4lb, 4lc. I resp. sub-circuit 34a, 34b, 34c circulates freon during the supply of compressor work and the transfer of heat between the heat exchangers H1 and H2, normally from H2 to H1, as indicated by the solid arrow P1 in Fig. 1. The reversing valves 36a, 36b, 36c can - is set by means of separate actuators 42a, 42b, 42c, whereby the direction of circulation is changed and heat is instead transferred from H1 with it to H2 (for cooling the supply air), as indicated by the dashed arrow P2 in Fig. 1.

I resp. channel branches 17, 18, 19 in the flow-through device 16 (compare Fig. 1), separate rotary dampers Sa, Sb, So are arranged, which are operated by associated actuating motors SP2, SP3, SP4 which are controlled from the control center RC for regulating the air flow through resp. channel branch in dependence on the pressure sensed by the pressure sensors 37a, 37b, 37c in resp. refrigerant sub-circuit. A separate rotary damper S1 in the bypass 20 (compare Fig. 1) is operated by means of the actuator motor SP1, so that the total supply air flow can be kept substantially constant.

The described device works as follows: Assume that the outdoor temperature is below about 1500 and that the room needs both heating and ventilation. Then the dampers 6, 8, 27 and 29 are placed in the shown, fully extended positions, whereby outdoor air U is sucked into the supply air duct system 2 and exhaust air E from the room is sucked in by means of the fan 21 in the exhaust air duct system 3, while the dampers 8 and 29 are closed. The outdoor air passes through the flow device 16, the various dampers S1, Sa, Sb, So (compare Fig. 2) being set separately by the control center RC depending on the sensed pressures in resp. refrigerant circuit in such a way that its pressure is kept constant and thus resp. condenser part Hla, Hlb, Hlc is kept at the desired temperature level, e.g. approx. 35 ° C (the reversing valves 36a, 36b, 36o are set so that the heat exchanger part H1 acts as a condenser and the heat exchanger part H2 acts as an evaporator). As mentioned above, the total supply air flow can be kept constant by appropriate adjustment of the damper S1 in the bypass 20.

The various refrigerant circuits 34a, 34b, 34c are actuated step by step by starting one or more of the compressors 35a, 35b, 35c at decreasing local temperature (which is sensed by T4 or T6). For maximum efficiency, this is dimensioned resp. condenser part with respect to a certain temperature increase of the incoming air for a given air flow.

Thus, in this exemplary embodiment, the first condenser part H1a is dimensioned to produce an air temperature increase of about 30, the second condenser part H1b to produce an increase of Go and the third condenser part H1c to produce an increase of about 120, which enables a division of the supplied power. in seven steps from a minimum increase of 30 to a maximum increase of 210. In the case of greater power requirements, a certain reheating of the supply air is required, which is achieved by means of the reheating battery 22 in the supply air duct system 2. Alternatively, this heat supplement can of course be supplied in another way. .ex. by means of radiators.

It is understood from the above that the temperature control can take place very accurately with very small oscillations in the supply air temperature, thanks to the separate temperature control in resp. condenser part and the constant maintenance of the total flow, while maintaining the maximum heat factor at the heat pump. When no air exchange is required in the room, e.g. at night or on weekends in a workroom, the dampers 6,8,27,29 are switched to their dashed positions, whereby the room air C is recirculated through the supply air duct system 2, while outdoor air U is sucked into the exhaust air duct system 3. The temperature control can now be carried out depending on the recirculated air temperature, which is sensed by T1. Heat is now pumped from the outdoor air U to the recirculated air, but otherwise the heat pump 1 and the flow-through device 16 operate in the same manner as in the previous case.

When the room temperature rises, the system can be reversed by adjusting the reversing valves 36a, 36b, 36c, so that the heat exchanger unit H1 functions as an evaporator and the heat exchanger unit H2 acts as a condenser. In this case, heat is pumped from the supply air (outdoor air U) to the exhaust air E (dashed arrow P2 in Fig. 1), whereby the supply air is cooled and the local temperature can be kept at a comfortable level. The temperature sensor T3 can check that the blown supply air does not have too low a temperature, which can be unhealthy. Otherwise, the system is controlled depending on the room temperature by means of T4 or T6.

The invention can be applied in many ways within the scope of the inventive concept. Thus, different temperature sensors, e.g.

T3, T4, T5, T6, control the temperature control, either individually or in combination with each other. The number of sub-circuits in the heat pump 1 can be selected as desired, whereby several compressors and condenser parts can be switchable in the same circuit. The number of power steps can also be selected as desired. As mentioned in the introduction, the heat exchanger battery H2, which normally operates as a evaporator, can also obtain heat from some other heat source than the exhaust air.

Claims (9)

8302895-1 10 ggTsNjrKRAv Heat pump device for temperature control and ventilation of a room, comprising a closed, compressor-driven refrigerant circuit (1) with a first, normally functioning condenser heat exchanger battery (H1), which is in heat-transmitting contact with the air flow in a supply air unit (2) , a throttle valve (39) and a second, normally evaporating heat exchanger battery (H2), which is in heat transfer contact with a medium which during normal operation emits heat to the refrigerant in the refrigerant circuit, characterized in that it the first heat exchanger battery (H1) is arranged in a flow-through device (16) provided with a bypass (20) in the supply air unit (2) and that means (S1, Sa, Sb, Sc) are arranged that during normal operation, ie. when the first heat exchanger battery (H1) is a condenser battery, for a given total flow in the supply air unit (2) distribute this total flow between the condenser battery (HI) and the bypass (20) depending on the temperature of the refrigerant in the condenser battery or a variable variable ( 37a, 37b, 37c). Heat pump device according to claim 1, characterized in that the condenser battery (H1) is divided into at least two condenser parts (H1a, H1b, H1c) arranged in each channel branch parallel to the bypass (20) in such a way that each condenser part holds desired temperature. Heat pump device according to Claim 1 or 2, characterized in that at least two compressors (35a, 35b, 35c) can be connected in stages in the refrigerant circuit (1). Heat pump device according to Claims 2 and 3, characterized in that the refrigerant circuit consists of at least two parallel sub-circuits (34a, 34b, 34c), each with its own compressor, condenser part, throttle valve and evaporator part (Fig. 2). 8302895-1 Heat pump device according to one of Claims 2 to 4, characterized in that separate dampers (Sl, Sa, Sb, Sc) are arranged to control the air flow in the bypass (20) and in resp. channel branch (l7, l8, l9). Heat pump device according to claims 4 and 5, characterized in that a separate sensor (37a, 37b, 37c) is arranged in resp. refrigerant sub-circuit for regulation of resp. condenser temperature, while a separate sensor (DP) is arranged in the supply air unit (2) for keeping the total supply air flow constant by controlling the damper (S1) in the bypass (20). Heat pump device according to one of Claims 2 to 6, characterized in that the condenser parts (Hla, Hlb, Hlc) are differently dimensioned in such a way that a stepwise increasing heat transfer to the supply air is obtained by connecting one or more condenser parts. in different combinations. Heat pump device according to any one of the preceding claims, wherein said second heat exchanger battery (H2) is arranged in an exhaust air unit (3), characterized V that in normal operation the inlet (4) of the supply air unit (2) communicates with outdoor air (U) and the intake (25) of the exhaust air unit (3) with exhaust air (E) from the room, the compressors or compressors (35a, 35b, 35c) of the refrigerant circuit being switched on depending on the exhaust air temperature, the supply air temperature, the room temperature and / or the outdoor temperature. Heat pump device according to claim 6, characterized in that in the event of reduced or no ventilation need in the room, the intake (5) of the supply air unit (2) communicates with the air (C) of the room, so that it is recirculated through the supply air unit (2), while the exhaust air unit (3) (26) communicates with outdoor air (U). 8302895-1 1-2 10. Heat pump device according to Claim 6 or 7, characterized in that the direction of circulation in the refrigerant circuit (1) is reversible, so that the first heat exchanger battery (H1) acts as an evaporator and the second heat exchanger battery (H2) acts as a condenser, whereby the supply air to the room can be cooled.