US20100242509A1

US20100242509A1 - Air routing for simultaneous heating and cooling

Info

Publication number: US20100242509A1
Application number: US12/746,420
Authority: US
Inventors: Alexander Lifson; Michael F. Taras
Original assignee: Individual
Current assignee: Carrier Corp
Priority date: 2007-12-07
Filing date: 2007-12-07
Publication date: 2010-09-30
Also published as: CN101889181B; CN101889181A; WO2009073036A1

Abstract

In an enclosed space which requires refrigeration or cooling at the same time when the heating of air is required, provision is made to divert at least a portion of the flow of heated air from the air conditioning/refrigeration heat rejection heat exchanger to the climate-controlled zone which requires heating. An airflow control device, such as one or more dampers, is provided for controlling the amount of heated air delivered to the climate-controlled-zone.

Description

TECHNICAL FIELD

This invention relates generally to refrigerant systems and, more particularly, to systems which are capable of simultaneously, providing cooling and heating.

BACKGROUND OF THE INVENTION

In a significant number of installations of heating, ventilation, air conditioning and refrigeration (HVAC&R) equipment, different climate-controlled zones have different requirements for cooling and heating. For instance, in supermarkets, there is generally a need for both refrigeration and for comfort cooling/heating. That is, there is a continuous need to maintain the refrigeration of both frozen and refrigerated goods. At the same, however, the climate-controlled environment for occupants (e.g. customers, service personnel, etc.) will require either air conditioning or heating, depending on the ambient temperature conditions and thermal load in the Conditioned space. Generally, for the cooling function, an air Conditioning system is provided, whereas for the heating function, a furnace, heat pump, electric heat or their combination is provided.
For both the refrigeration system and the air conditioning system, one or more heat rejection heat exchangers must be provided to cool the refrigerant vapor coming, from the compressor. As known, the heat rejection heat exchanger is a condenser for subcritical applications and a gas cooler for transcritical applications. Generally, the heat rejection heat exchangers for air conditioning and large refrigeration equipment have been located outside of the enclosed space with the heat being discharged to ambient environment. At times, however, it has been found to be more convenient to install the heat rejection heat exchanger inside the supermarket spade such as a machine room. In such case, the heat has generally been allowed to be dissipated within the space. In any case, there has been no effort to strategically use the heat dissipated by the heat rejection heat exchanger for heating purposes within the enclosed space. The, enclosed space may be any space where the air needs to be conditioned. The enclosed space, for example, may be a space within a building such as a supermarket, commercial building, school, hospital or residence.
It is common in air conditioning systems to provide conditioned air which is caused to flow to various zones within the building. The temperature in each zone is monitored and maintained by controlling the flow of conditioned air to each zone. Because of differences in space usage, occupancy, ideation, equipment, etc., there may be one or more spaces which require air conditioning at a particular time when, at the same time, one or more other spaces require heat in order to maintain the desired temperatures. In such cases, the heat has generally been applied by way of resistance coils that are electrically heated. Again, no effort has been made to use the heat from the condensers for that purpose.

DISCLOSURE OF THE INVENTION

In accordance with one aspect of the invention, a refrigerant system includes a heat accepting heat exchanger to selectively provide cooling to some climate-controlled zones and a heat rejection heat exchanger to selectively provide heating to other climate-controlled zones when required. In one embodiment, one or more air dampers are used to direct flow either from the heat accepting heat exchanger to selectively cool a particular climate-controlled zone or to direct flow from the heat rejection heat exchanger to selectively heat the climate-controlled zone. An option to bring an untreated “fresh” ambient may also be provided.
In another embodiment, an HVAC&R system includes an air conditioning subsystem and a refrigeration subsystem, each of which has the associated heat rejection heat exchanger to remove heat from the refrigerant compressed in the compressor, while heating air in the process. Each air stream passing through the associated heat rejection heat exchanger may flow through a damper selectively positioned so as to discharge the heated air either into the building or outside the building being conditioned/refrigerated, or both. In one example, both air conditioning and refrigeration subsystems have the same heat rejection heat exchanger that is utilized for heating purposes of a particular climate-controlled zone.
By other aspect of the invention, a method of operating an air HVAC&R system includes the steps of providing a discharge duct for conducting the flow of heated air from a heat rejection heat exchanger and an airflow control device, such as a damper, for selectively directing the flow of heated air into the building, outside of the building or both.
In the drawings as hereinafter described, a preferred embodiment is depicted; however, various other modifications and alternate constructions can be made thereto without departing from the Spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a supermarket building with the present invention incorporated therein.

FIGS. 2-4 are schematic illustrations of the damper portion of the present invention as shown in three different operating positions.

FIG. 5 is a schematic illustration of a zoned building for which the present invention maybe applied.

DETAILED DESCRIPTION OF THE INVENTION

Shown generally at 11 in FIG. 1 is a supermarket building layout having a climate-controlled customer shopping area 12 and a refrigerated section 13, which may include climate-controlled environments for both low temperature deep frozen goods and medium temperature refrigerated produce.
The customer shopping area 12 is preferably maintained within a comfort zone, with respect to temperature and humidity, that may depend on the time of the year and geographic location. In order to accomplish this task of maintaining the comfort conditions, it is typically necessary to have both an air conditioning cooling system and some type of a heating system, a combination of which is identified by the numeral 14. Generally, the air conditioning subsystem will be in operation during the cooling season (typically, summer months), the heating subsystem will be in operation during the heating season (typically, winter months), and one or the other will be in operation during the transitional periods (typically, spring and fall) therebetween. One or more thermostats 16 are typically provided to sense the temperature in the customer shopping area 12 for the purpose of controlling the HVAC system 14 by way of a control 17. The control 17 may be the HVAC system 14 control or the overall supermarket building control.
The refrigerated area 13 includes one or more associated refrigeration systems 18, potentially operating at different temperatures, each of which includes, in serial flow relationship, at least one compressor, heat rejection heat exchanger, expansion device and evaporator. The expansion device and the evaporator are typically located within or near the refrigerated enclosure, display or the like, while the compressor and heat rejection heat exchanger are generally located outside the refrigerated climate-controlled zone, such as in a machine room or outside the building.
The heat rejection heat exchanger of the “outdoor” section which is shown at 19, removes heat from the refrigerant vapor discharged from the compressor, and may be either of an air cooled type or a water cooled type, but is most commonly cooled by air in supermarket installations. During heat transfer interaction between refrigerant and air in the heat rejection heat exchanger, the air is thus heated, and the heated air is normally discharged to the ambient environment. The present invention is intended to use this heated air during periods in which the customer shopping area 12 is or may otherwise be heated by way of the heating subsystem of the HVAC system 14.
The heat rejection heat exchanger section 19 may include an airflow directing device such as a pair of dampers 21 and 22 which are operative to selectively open or close the respective openings 23 and 24. The opening 23 leads from the heat rejection heat exchanger section 19 to the customer shopping area 12, and the opening 24 leads from the heat rejection heat exchanger section 19 to ambient environment. The two dampers 21 and 22 are selectively operated by the control 17.
As is seen in FIG. 1, the ambient air enters the heat rejection heat exchanger section 19 as indicated by the arrows 26. After having passed through the heat rejection heat exchanger section 19 and having been heated in the process by the refrigerant, the air can then be selectively passed through the opening 23 or the opening 24 or both, depending on the positions of the dampers 21 and 22.
In operation, during periods in which the air conditioning subsystem of the HVAC system 14 is operating to cool the customer shopping area 12, the damper 21 will be closed and the damper 22 will be open such that the ambient air passes through the heat rejection heat exchanger section 19 and the heated air then passes back to ambient environment. During periods in which the heating subsystem of the HVAC system 14 is or would otherwise be in operation to heat the customer shopping area 12, the damper 21 may be opened to allow the heated air from the heat rejection heat exchanger section 19 to pass through the opening 23 and into the customer shopping area 12. During these periods of operation, the damper 22 may be closed such that all of the heated air will enter the customer shopping area 12, or it may be left partially opened such that some of the heated air enters the customer shopping Area 12 and some of it is passed through the opening 24 to be discharged to ambient environment. The control 17 is therefore operated to selectively control the two dampers 21 and 22 in response to the sensed temperature from the thermostat 16 and the HVAC system 14 as controlled by the control 17.
It should be understood that the damper combination 21 and 22 as shown may be of various types and form. That is, although it is shown as two dampers 21 and 22, it may comprise only a single damper which provides the pathway between the heat rejection heat exchanger section 19 and the customer shopping area 12.
It has to be pointed out that the heated air from the heat rejection heat exchanger section 19 may be a sole source of heating or may be an additional heat source. Further, the HVAC system may have the capability to bring a “fresh” untreated portion of air from the ambient environment when desired.
Referring now to FIGS. 2-4, there is generally shown a condenser section 27 that is fluidly connected to a duct 28 by way of a damper 29 The damper 31 includes two louvered sides 32 and 33, with side 32 leading to a portion 34 of the duct 29 which discharges to ambient and the side 33 leading to a portion 36 of the duct 29 leading to the customer area 12.
In FIG. 2, the damper 32 is closed and the damper 33 is open to allow the heated air from the heat rejection heat exchanger section 27 to pass to the indoor environment, i.e. the customer area, to thereby provide supplemental or primary heat during periods in which heating, of the customer area is required. In FIG. 3, the damper 32 is open and the damper 33 is closed, such that the heated air from the heat rejection heat exchanger section 27 passes to the outdoor environment The system would operate in this mode during all periods in which heating of a space is not required. As shown in FIG. 4, both dampers 32 and 33 are open such that some of the heated air from the condenser section passes through a duct 34 to then flow to the outdoor environment, while some of the heated air passes to the-duct portion 36 to provide heat to the indoor environment. The louvers in the dampers 32 and 33 are, of course, controllable to any position, between the fully opened and the fully closed position, to thereby permit any of various positions as determined by the control or the operator, thus providing variable controllable amounts of heat from the heat rejection heat exchanger section 27 to the indoor environment. As was mentioned above, in some applications, in order to satisfy fresh air circulation requirements for the building, a portion of ambient air need to be continuously brought up into the indoor environment. During periods of time when heating in the indoor environment is required and according to the invention, this ambient air is first flown through the heat rejection heat exchanger section 27. It should be understood that to prevent building over-pressurization, pressure relief means, such as barometric relief, are usually installed to allow discharging some amount of air, in case the pressure in the building becomes higher than desired.
In addition to the supermarket application as described hereinabove, the present invention can also be used in a zoned building wherein, as shown in FIG. 5, plurality of climate-controlled zones, indicated at 37, 38, 39 and 41 are each fluidly connected to a HVAC system 42 by respective conditioned air discharge duct openings 43, 44, 46 and 47. Each of the climate-controlled zones has one or more thermostats for controlling the temperature within that zone, independent or the other zones. Thus, depending on various factors as discussed hereinabove, one zone may be in need of colder air to be delivered thereto while another zone may need heated air being delivered thereto. During such periods of operation, the air conditioner would be in operation, and the associated heat rejection heat would be actuated to heat ambient air. Thus, that heated air could be passed to the zone which was in need of heated air at that time. The damper and control system as described hereinabove would therefore be applicable to such an installation.
It should be understood that similar methodology may be applied for temperature control purposes. For instance, if one compartment of a multi-level refrigeration system requires a temperature different from that of another compartment, or if one climate-controlled zone needs a temperature different from that another climate-controlled zone, a portion of air discharged from the heat rejection heat exchanger may be used for this temperature control purpose.
While the present invention has been particularly shown and described with reference to a preferred and modified embodiment as illustrated in the drawings, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

1. An air conditioning system, a refrigeration system, or a combination thereof, comprising:

a compressor, a heat rejection heat exchanger, an expansion device and an evaporator in a serial flow relationship, with the evaporator for cooling air, and the heat rejection heat exchanger for heating air;

a discharge air duct for conducting the flow of heated air from the heat rejection heat exchanger; and

an airflow control device for selectively directing at least a portion of the heated air in the discharge air duct to either a location within an enclosed space and/or to an ambient environment.

2. A system as set forth in claim 1 wherein airflow control device is at least one damper.

3. A system as set forth in claim 2 wherein said at least one damper is a pair of dampers.

4. A system as set forth in claim 2 wherein said at least one damper is a two-position damper.

5. A system as set forth in claim 2 wherein said at least one damper is a multi-position damper such that some of the heated air is passed into the enclosed space and some of the heated air is passed to an ambient environment.

6. A system as set forth in claim 1 wherein the heated air is utilized to satisfy fresh air circulation requirements.

7. A system as set forth in claim 1 wherein the heated air is utilized for a zone temperature control.

8. A system as set forth in claim 1 wherein the enclosed space is a space within a building.

9. A system as set forth in claim 1 wherein the refrigeration system is a supermarket refrigeration system.

10. A system as set forth in claim 1 wherein said system at times provides both refrigeration and heating.

11. A system as set forth in claim 1 wherein the system comprises a multi-zone system associated with multiple climate-controlled zones wherein one or more zones may require cooling while, at the same time, one or more zones may require heating.

12. A method of operating an air conditioning system, a refrigeration system or a combination thereof, comprising the steps of:

providing an evaporator for cooling air;

providing a heat rejection heat exchanger for heating air;

providing a discharge air duct for conducting the flow of the heated air from the heat rejection heat exchanger; and

selectively directing at least a portion of the heated in the discharge air duct to either a location within an enclosed space and/or to an ambient environment.

13. A method as set forth in claim 12 wherein said flow directing step is by way of at least one damper.

14. A method as set forth in claim 13 wherein said at least one damper is a pair of dampers.

15. A method as set forth in claim 13 wherein said at least one damper is a two-position damper.

16. A method as set forth in claim 13 wherein said at least one damper is a multi-position damper such that some of the heated air is passed into the enclosed space and some of the heated air is passed to an ambient environment.

17. A method as set forth in claim 12 wherein the heated air is utilized to satisfy fresh air circulation requirements.

18. A method as set forth in claim 12 wherein the heated air is utilized for a zone temperature control

19. A method as set forth in claim 12 wherein the enclosed space is a space within a building.

20. A method as set forth in claim 12 wherein the refrigeration system is a supermarket refrigeration system.

21. A method as set forth in claim 12 wherein said system at times provides both refrigeration and heating. 2,2. A method as set forth in claim 12 wherein the system comprises a multi-zone system associated with multiple climate-controlled zones wherein one or more zones may require cooling while, at the same time, one or more zones may require heating.