MXPA06009422A - Hybrid dehumidication system - Google Patents

Abstract

A hybrid dehumidification system includes a compressor, a condenser, an expansion device and an evaporator connected for flow of working fluid through a fluid circuit;a reheat coil positioned relative to the evaporator for heating at least a portion of a stream of air passing through the evaporator;and a working fluid directing system adapted to flow working fluid in at least two modes of operation selected from the group consisting of a standard cooling mode, a cooling and enhanced dehumidification mode;a dehumidification without substantial sensible capacity mode;a heating and dehumidification mode;and a dehumidification with variable sensible capacity mode.

Description

- - HYBRID DEHUMIDIFICATION SYSTEM BACKGROUND OF THE INVENTION The invention relates to a system which can provide heating, ventilation, air conditioning and cooling functions as well as dehumidification in a versatile and efficient manner. Dehumidification is often needed in conditioned spaces that use different units or systems of heating, ventilation, air conditioning and refrigeration (HVAC and R). This dehumidification may be desirable in both hot and cold environments. Conventional systems are limited in the applicability of the dehumidification function and may be inefficient under certain circumstances. There is a need for an improved system to provide dehumidification in different system conditions as needed, in an efficient manner. Therefore, the main objective of the present invention is to provide said system. A further objective of the invention is to provide a method of operation of said system. Other objects and advantages of the present invention will now be apparent in the following.

- - BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, the above objects and advantages are easily obtained. According to the invention, a hybrid dehumidification system is provided which comprises: a compressor, a condenser, an expansion device and an evaporator connected for flow of working fluid through a circuit; an overheating coil positioned in relation to the evaporator for heating at least a portion of the air vapor passing through the evaporator; and a means for providing flow of working fluid in at least two modes of operation that are selected from the group consisting of: a cooling mode wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the device of expansion, from the expansion device to the evaporator and from the evaporator to the compressor; an improved cooling and dehumidification mode, wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the reheat coil, from the reheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; - a dehumidification mode without substantial sensible capacity, in which the working fluid flows sequentially from the compressor to the superheat coil, from the superheat coil to the condenser, from the condenser to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; a heating and dehumidification mode wherein the working fluid flows sequentially from the compressor to the reheat coil, from the reheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; and a dehumidifying mode with variable sensitive capacity wherein the working fluid flows sequentially from the compressor in a first portion to the condenser and in a second portion around the condenser, the first and second portions then flow to the superheat coil, from the coil from reheating to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor. In further accordance with the invention, there is provided a method for operating a system according to the invention so that operation is provided in a suitable manner in a plurality of ways by means of which cooling is provided as needed. heating and dehumidification.

BRIEF DESCRIPTION OF THE DRAWINGS The following is a detailed description of the preferred embodiments of the invention, in which reference is made to the accompanying drawings, in which: Figure 1 illustrates schematically a system according to the invention, together with the operation of the system in an operation mode to provide cooling; Figure 2 illustrates a system according to the invention in an operation mode for providing cooling and dehumidification; Figure 3 illustrates a system according to the invention in an operation mode for providing dehumidification with negligible sensitive capacity; Figure 4 illustrates a system according to the invention in an operation mode for providing heating and dehumidification; Figure 5 illustrates a system according to the present invention in an operation mode for providing dehumidification and sensitive-variable capacity; and Figure 6 illustrates an alternative useful configuration for providing operation, according to the invention.

DETAILED DESCRIPTION The invention relates to heating, ventilation, air conditioning and cooling systems and, more particularly, to such a system adapted to provide dehumidification in a plurality of different operating modes adapted to various environmental conditions as well as sensitive capacity demands. and latent. According to the invention, a cooling system is provided with additional flow segments and flow control valves together with a control unit adapted to operate the same by means of which a plurality of operating modes are available with the system. different These different modes of operation make the system suitable for use in a wide variety of market requirements, and can respond to diverse needs in terms of latent and sensitive capacity and environmental conditions. Figure 1 illustrates a system 10 according to the invention which includes a compressor 12, a condenser 14, an expansion device 16 and an evaporator 18, all connected by a working fluid circuit 20 which includes a segment 22 which is it directs from the compressor 12 to the condenser 14, a segment 24 which is directed from the condenser 14 to the expansion device 16, a segment 26 which is directed from the expansion device 16 to the evaporator 18, and a segment 28 which is directed from the evaporator 16 back to the compressor 12. This system works in a well-known manner to condition a stream 30 of air passing through the evaporator 18, typically to cool, heat or dehumidify the same. Still with reference to Figure 1, the system 10 also includes a reheat coil 32 which is arranged to condition at least a portion of the stream 30. The reheat coil 32 can advantageously be used to reheat the current 30. According to the invention, the components described in the above are connected by a series of additional flow segments and the refrigerant flows through its components is controlled with flow control device, such as valves, so that a plurality is provided of different desirable operating modes. These modes include a conventional cooling mode, where no special means is applied to change the relationship between the latent and sensible operation of the system, an improved cooling and dehumidification mode, a dehumidification mode with negligible sensitive capacity, a mode of heating and dehumidification and a dehumidification mode with variable sensitive capacity. Each of these operating modes can be selected for operation based on the conditions detected or the instructions entered by a user so as to provide the desired function. In the embodiment shown in the drawings, these additional flow segments and valve device include a reheat segment including a segment 34 connected between line 22, upstream of condenser 14 and reheat coil 32, and a segment 36 connected between the reheat coil 32 and the line 24 downstream of the condenser 14. A three-way valve 38 can be placed at the junction between line 22 and segment 34 to control the flow therebetween, and can be provided a shut-off valve 40 along line 36 also. A warm-water reheating segment may also be provided as illustrated, which includes a segment 42 which is directed from line 24 downstream of the condenser to line 34 for feeding to the reheat coil 32. According to the invention, a track valve 43 can be placed at the junction between line 24 and segment 42 to control the flow between them. A reheat work fluid recycle segment can also be provided which includes a segment 44 connected between the segment 36 and the line 22 for transporting the superheated working fluid from the reheat coil 32 back to an inlet of the condenser 14. A shut-off valve 46 can be placed along the segment 44 to control the flow therethrough. further, a capacitor shunt segment can be provided and includes a segment 48 which communicates between the line 22 downstream of the capacitor 14 and the line 24 downstream of the capacitor 14. A shut-off valve 50 can be placed along the length of the segment 48 and can be used to control the flow through it. Figures 1 to 5 illustrate the system described in the above in 5 different operating modes that can be named based on the requirements, according to the environmental conditions and the demands of latent and sensitive capacity. These figures show values in the open / closed or open positions in a particular direction as well as arrows showing the refrigerant flow in each mode. Figure 1 illustrates the system that is operated in a conventional cooling mode and shows open and closed valves for this mode as well as the working fluid flow. As shown, in this mode of operation a three-way valve 38 is opened to the condenser 14 and the three-way valve 43 opens to the expansion device 16. All of the closing valves 40, 46 and 50 are closed. In this embodiment, the working fluid flows through the working fluid circuit 20, to provide maximum sensitive cooling to the air passing through the evaporator 18. In this operating mode, the working fluid is not actively circulated to through the reheating coil 32. Figure 2 illustrates an operation mode wherein both improved cooling and dehumidification are provided. This may be desirable in cases where cooling is needed but the system can handle additional dehumidification demands as well. In this mode of operation, the three-way valve 38 opens towards the condenser 14 and the path valve 43 opens towards the reheating coil 32. The shut-off valve 40 is opened and the valves 46 and 50 are closed. In this configuration, the entire coolant flow is directed from the condenser to the reheat coil 32 as a warm liquid, and from the reheat coil 32 to the device 16 of expansion and through the remainder of the circuit, as shown by the arrows in Figure 2. This mode of operation allows the subcooling of additional refrigerant and improved dehumidification of the air stream 30 passing through the evaporator 18, followed by certain overheating of the air stream, as is known in the art. Figure 3 illustrates the system configured to operate in a dehumidification mode with a usually insignificant sensible capacity. In this mode of operation, the three-way valve 38 is opened from the reheating coil 32 while the three-way valve 43 is opened to the exiting device 16. The shut-off valve 46 is opened while reheating before being fed to the condenser 14 and, in this way, dehumidification can be carried out with a minimum total sensible capacity or cooling of the air stream 30. Figure 4 illustrates an operation mode where heating and dehumidification is provided. In this operating mode the three-way valve 38 is opened towards the reheating coil 32 and the three-way valve 43 is opened towards the expansion device 16. The closing valve 40 is opened, while the valve 46 is preferably closed. The position of the valve 50 in this mode is not critical. In this mode of operation, the hot gas from the compressor 12 is first fed to the reheating coil 32 and then to the expansion device 16 and back to the evaporator 18 so as to provide heating and dehumidification of the air stream 30. FIG. shows an operation mode where dehumidification with variable sensitive capacity is provided. In this mode of operation, the three-way valve 38 is directed towards the condenser 14, while the three-way valve 43 is directed towards the reheating coil 32. The shut-off valves 40 and 50 are opened and the valve 46 is closed. In this embodiment, a first portion of a hot gas from the compressor 12 is passed through the condenser 14 while a second portion is allowed to be derived or flow around the condenser 14 through line 48 resulting in a two-phase mixture being fed to the reheat coil 32 to be subcooled and then fed to the expansion device 16. Depending on the portion of the flow that passes through line 48, variable capacity can be provided. Valve 50 can be used as a flow control device, if desired. In further accordance with the invention, a control unit 51 (FIG. 1) is provided and communicates with each of the valves described therein, and also with the sensors for various environmental parameter measurements, and the received capacity is input to allow to the user to program, for example, the desired temperature, humidity and enthalpy and the like. These communications are schematically illustrated by arrow 53. The actual components of such a control mechanism include sensors, valve controllers, processing units and programming techniques, and are well known to a person ordinarily skilled in the art. According to the invention, such a control system is advantageously adapted to detect which type of operation mode is needed to be based on what the user enters such as the desired temperature, humidity or enthalpy and environmental factors such as interior temperature, outside temperature, humidity, suction pressure, discharge pressure, saturated suction temperature, saturated discharge temperature, return air temperature, supply air temperature, supply air enthalpy, return air enthalpy and combinations and It adapts additionally to send appropriate signals to these valves so that they open / close them and provides the desired mode of operation. It should be appreciated that the valves described herein can be substituted with other types of flow control devices and that the main function of the valves and the ability to control the flow as described herein. For example, instead of three-way valves, a pair of solenoid valves can be used to provide the same function. It is possible to replace pairs or triple sets of shut-off valve with 3-way or 4-way valves, accordingly, all within the scope of the present invention. Instead of the shut-off valves and the two-way, three-way valves that are described herein, regulating devices can be used so as to allow gradual changes in the refrigerant flow which can be used by the control system to optimize the operation of the system. It should be evident that lines 48 and 44 which contain the valves 50 and 46 respectively, they can change position one in relation to the other as known by a person skilled in the art. It should also be understood that a purge circuit or a hot gas bypass circuit can be added to the scheme to prevent charge migration and evaporator freezing, respectively. It should also be appreciated that although Figures 1 to 5 herein show a specific configuration of circuit and segments for transporting working fluid, these flow lines and segments can be configured differently while performing the same function, and that all modifications they are within the scope of the present invention. For example, Figure 6 illustrates a modification of the system shown in Figures 1 to 5 where a valve 52 is placed upstream of the condenser 14. This valve 52 can be used to control the amount of flow between the condenser 14 and the bypass line 48 and thus an alternative solution to the variable sensitive capacity provided by the operation mode of Figure 5 is provided. In addition, the closing of the valve 52 as a whole while the valves 40 and 50 are opened, the valve 46 is closed and the valve 43 directed to the reheating coil 32 provides an alternative solution to the bypass condenser 14 completely and provides function as in the operation mode of Figure 4, for heating with positive dehumidification. With the valve 52, it is possible to completely remove the valve 38 and still provide the desired modes of operation. Based on the above, it should be appreciated that many alternative configurations of lines and types of valve placement can be used to provide the desired functional modes and that such alternative configurations are within the broad scope of the present invention. It is clear that a hybrid dehumidification system has been provided in accordance with the present invention wherein improved operation is provided through the multiple operation mode. This completely satisfies the objectives, means and advantages previously established in this document. Although the present invention has been described in the context of specific embodiments thereof, other alternatives, modifications and variations will be apparent to those skilled in the art upon reading the foregoing description. Accordingly, it is intended to cover all these alternatives, modifications and variations insofar as they fall within the broad scope of the appended claims.

Claims (8)

- CLAIMS

1. Hybrid dehumidification system, comprising: a compressor, a condenser, an expansion device and an evaporator connected for working fluid flow through a circuit; an overheating coil positioned in relation to the evaporator for heating at least a portion of a stream of air passing through the evaporator; and a working fluid targeting means for flowing the work flow in at least two operating modes that are selected from a group of modes consisting of: a cooling mode wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; an improved cooling and dehumidification mode, wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the superheat coil, from the superheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; a dehumidification mode without substantial • sensitive capacity where the working fluid flows sequentially from the compressor to the reheating coil, from the reheat coil to the condenser, from the condenser to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; a heating and dehumidification mode wherein the working fluid flows sequentially from the compressor to the superheat coil, from the reheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; and a dehumidifying mode with variable sensitive capacity wherein the working fluid flows sequentially from the compressor in a first portion to the condenser and in a second portion around the condenser, the first and second portions then flow to the superheat coil, of the overheating the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor. System as described in claim 1, wherein the working fluid targeting means comprises means for selectively flowing working fluid in all modes of operation. System as described in claim 1, wherein the working fluid addressing means comprises: a reheat coil addressing connected between the working fluid circuit upstream of the condenser and the superheat coil, and between the reheating coil and the working fluid circuit downstream of the condenser and upstream of the expansion device; a hot water reheating segment connected between the working fluid circuit downstream of the condenser and the superheat coil; a recycle segment of reheat work fluid connected between the reheat coil and the working fluid circuit upstream of the condenser; and a capacitor bypass circuit connected between the working fluid circuit upstream of the condenser and the working fluid circuit downstream of the condenser. A system as described in claim 3, further comprising a first three-way valve positioned between the working fluid circuit and the reheat segment, a second three-way valve placed between the working fluid circuit and the recycle segment of reheating work fluid and shut-off valves placed in the reheat work fluid recycling segment, the reheat segment and the condenser bypass segment. System as described in claim 4, wherein at least one of the first, second and third three-way valve and shut-off valves is a regulating valve. System as described in claim 4, further comprising a control member adapted to operate the first and second three-way valves and shut-off valves based on the operating demands of the system. Method for operating a hybrid dehumidification system, comprising the steps of: providing a refrigeration system comprising a compressor, a condenser, an expansion device and an evaporator connected for flow of working fluid through a circuit; an overheating coil positioned in relation to the evaporator to heat at least a portion of a stream of air passing through the evaporator; and working the fluid addressing means for flowing the working fluid in at least two modes of operation which are selected from a group of modes consisting of: a cooling mode, wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; an improved cooling and dehumidification mode, wherein the working fluid flows sequentially from the compressor to the condenser, from the condenser to the reheat coil, from the reheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; a dehumidification mode without substantial sensible capacity wherein the working fluid flows sequentially from the compressor to the superheat coil, from the superheat coil to the condenser, from the condenser to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; a heating and dehumidification mode wherein the working fluid flows sequentially from the compressor to the superheat coil, from the reheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; and a dehumidifying mode with variable sensitive capacity wherein the working fluid flows sequentially from the compressor in a first portion to the condenser and in a second portion around the condenser, the first and second portions then flow to the superheat coil, of the superheat coil to the expansion device, from the expansion device to the evaporator and from the evaporator to the compressor; detect a desired mode of operation of the mode group; and operating the working fluid targeting means to provide the desired mode of operation. 8. Method as described in the claim 7, wherein the detection step comprises detecting at least one value that is selected from the group consisting of indoor temperature, outside temperature, humidity, suction pressure, discharge pressure, saturated suction temperature, saturated discharge temperature, temperature return air, supply air temperature, supply air enthalpy and return air enthalpy and combinations thereof, and use at least one value to determine the desired mode of operation.