Thermal System Including an Environmental Test Chamber

A system is provided where the system includes a chamber, a first cooling system including a first cooling load evaporator, wherein the first cooling system is placed within the chamber, a second cooling system including a fluid coil, wherein the fluid coil is placed within the chamber, and a thermal storage for a second cooling fluid in the second cooling system, wherein the thermal storage is placed outside the chamber. In the system, the first cooling system further includes a first compressor and a first condenser and the second cooling system further includes a thermal storage chiller, wherein the thermal storage chiller is placed outside the chamber.

The invention relates to a thermal system including an environmental test chamber, and more particularly, to a thermal system including an environmental test chamber equipped with a plurality of cooling systems and a method for manufacturing the system.

BACKGROUND OF THE INVENTION

An environmental test chamber is typically equipped with a single refrigeration system to accommodate various test conditions. Because the test conditions impose large temperature changes in short periods of time, the test chamber contains a large capacity refrigeration system that is capable of imposing a temperature change from 150° C. to −65° C. As the capacity becomes larger, the refrigeration system can accommodate larger temperature changes but requires more energy consumption. The test chamber is operated in various temperature ranges. Simply increasing the capacity of the single refrigeration system may cause unnecessary energy consumption. In addition, a single refrigeration system does not adequately respond to a fast temperature change. For example, when a large amount of heat is dissipated in the test chamber in a short amount of time, the single refrigeration system can be quickly overpowered.

Therefore, there is a need for improved environmental test chamber to address the issues that a single large refrigeration system imposes.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, a system is provided. The system includes a chamber, a first cooling system including a first cooling load evaporator, wherein the first cooling system is placed within the chamber, a second cooling system including a fluid coil, wherein the fluid coil is placed within the chamber, and a thermal storage for a second cooling fluid in the second cooling system, wherein the thermal storage is placed outside the chamber. In the system, the first cooling system further includes a first compressor and a first condenser, and the second cooling system further includes a thermal storage chiller, wherein the thermal storage chiller is placed outside the chamber. The first cooling system may include a single compressor.

In another aspect, the first cooling system further includes a low stage loop including a low stage compressor and the first cooling load evaporator, a high stage loop including a high stage condenser and a high stage compressor, and a cascade condenser, wherein the low stage loop is configured to process a low stage working fluid and the high stage loop is configured to process a high stage working fluid, wherein the low stage loop and the high stage loop are connected to the cascade condenser, and wherein the system is configured to process the low stage working fluid, the high stage working fluid, and the second working fluid separately from each other within the system.

In another aspect, the system further includes one or more valves, wherein the valves are configured to adjust an amount of the second working fluid flowing into the fluid coil in the second cooling system. In some aspects, the system further includes one or more valves, wherein the valves are configured to adjust amounts of the low stage working fluid, the high stage working fluid and the second working fluid flowing in the system, respectively.

In another aspect, the system further includes one or more expansion devices and a controller, wherein the controller is configured to control the first cooling system and the second cooling system, wherein the controller is configured to activate the second cooling system when the first cooling system is being operated at full capacity, wherein the controller is further configured to activate the second cooling system when a cooling rate of the chamber is less than a target cooling rate, wherein power of the second cooling system is equal to or less than power of the first cooling system, and wherein the second cooling system further includes a brine pump.

In another embodiment, a method for manufacturing a system is provided. The method includes preparing a first cooling system including a low stage loop, a high stage loop, and a cascade condenser, placing the first cooling system inside a test chamber; connecting the low stage loop to the cascade condenser, connecting the high stage loop to the cascade condenser, preparing a second cooling system including a fluid coil, a thermal storage to store the second working fluid, and a thermal storage chiller, placing the fluid coil inside the test chamber, placing the thermal storage outside the test chamber; and placing the thermal storage chiller outside the test chamber.

In another aspect, the method further includes configuring the second cooling system to process the second working fluid in the second cooling system separate from the first cooling system, connecting a controller to the first cooling system, connecting the controller to the second cooling system, configuring the controller to activate the second cooling system when a cooling rate of the test chamber is less than a target cooling rate, preparing a low stage working fluid for the low stage loop, preparing a high stage working fluid for the high stage loop, and configuring the first cooling system to separately flow the low stage working fluid and the high stage working fluid from the second working fluid.

In another embodiment, an apparatus is provided. The apparatus includes a chamber, means for evaporating a first cooling medium, wherein the means for evaporating the first cooling medium is placed inside the chamber; means for evaporating a second cooling medium, wherein the means for evaporating the second cooling medium is placed inside the chamber; means for storing the second cooling medium, wherein the means for storing the second cooling medium is placed outside the chamber, and wherein the second cooling medium separately flows from the first cooling medium within the apparatus.

There has thus been outlined, rather broadly, certain aspects of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional aspects of the invention that will be described below and which will form the subject matter of the claims appended hereto.

DETAILED DESCRIPTION OF THE INVENTION

An aspect of the disclosure is directed to a thermal system including a first cooling system, a second cooling system and a test chamber, wherein the test chamber includes a first cooling system and is connected to the second cooling system.

FIG. 1is a schematic diagram showing an exemplary thermal system including a test chamber according to the disclosure. In particular,FIG. 1is a schematic diagram showing an exemplary thermal system1including a test chamber10according to the disclosure. The test chamber10may include a first cooling system100. In addition, the test chamber10may be connected to a second cooling system200.

The first cooling system100may include a first cooling load evaporator111, an expansion device104, a first compressor102and a first condenser103. The first cooling system100may process a first working fluid when the first working fluid enters the first cooling load evaporator111. The first working fluid may be evaporated in the first cooling load evaporator111to form a first working vapor by absorbing heat from the ambient air.

The first working vapor may exit the first cooling load evaporator111and enter the first compressor102, The first compressor102may compress the first working vapor, thereby increasing the pressure and the temperature of the first working vapor. The compressed first working vapor may exit the first compressor102and then circulate to the first condenser103. The compression of the first working vapor may be through a single compressor.

While traveling through the first condenser103, heat may flow out of the first working vapor, thereby cooling the first working vapor. The first working vapor may be condensed and liquefied. The first working fluid may exit the first condenser103and then circulate to the first expansion device104. The first expansion device104may substantially reduce the pressure and the temperature of the first working fluid that may circulate through the first cooling system100, The first working fluid exiting the first expansion device104may circulate to the first cooling load evaporator111.

The second cooling system200may include a fluid coil201, a thermal storage203, and a thermal storage chiller202. In one aspect, the thermal storage203may be placed outside the test chamber10. In some aspects, the thermal storage203and the thermal storage chiller202may be placed outside the test chamber10. In various aspects, the fluid coil201may be placed inside the test chamber10.

The second working fluid from the thermal storage203may enter a second expansion device209. The second expansion device209may substantially reduce the pressure and the temperature of the second working fluid that may circulate through the second cooling system200, The second working fluid exiting the second expansion device209may circulate to the fluid coil201.

In the fluid coil201, the temperature of the second working fluid may increase by absorbing heat from the ambient air while traveling through the fluid coil201. The heated second working fluid or vapor may circulate to the thermal storage chiller202.

In one aspect, the thermal storage chiller202may be placed outside the test chamber10. The second working fluid may be condensed and cooled and/or liquefied while traveling through the thermal storage chiller202.

The cooled second working fluid exiting the thermal storage chiller202may enter the thermal storage203. In one aspect, the thermal storage203may be placed outside the test chamber10. The operating temperature of the thermal storage may be in a range of from about 75° C. to about 210° C. In various aspects, the thermal storage203may lower the temperature of the second working fluid entering the thermal storage203. For example, the thermal storage203may lower the temperature of the second working fluid entering the thermal storage203by 2° C. or more, preferably 10° C. or more.

FIG. 2depicts a schematic diagram showing an exemplary thermal system1including a test chamber10according to the disclosure. The test chamber10may include a first cooling system100with a cascade condenser130. The test chamber10may be further connected to a second cooling system200.

The first cooling system100may include a low stage loop110, a high stage loop120and a cascade condenser130. The low stage loop110may process a low stage working fluid. The low stage loop110may include a low stage compressor112and a first cooling load evaporator111. The low stage loop110may be connected to the cascade condenser130.

The low stage working fluid may be a refrigerant. In one aspect, the low stage working fluid may be any suitable working fluid for a particular application of the system such as flammability, toxicity, or the like. In some aspects, the low stage working fluid may include fluoride. In various aspects, the low stage working fluid may include fluoroolefiris.

The low stage loop110may optionally include a low stage expansion device113. The low stage expansion device113may substantially reduce the pressure and the temperature of the low stage working fluid that may circulate through the low stage loop110. The low stage working fluid exiting the low stage expansion device113may circulate to the first cooling load evaporator111.

In the first cooling load evaporator111, the low stage working fluid may be evaporated to form a low stage working vapor by absorbing heat from the ambient air while traveling through the first cooling load evaporator111.

The low stage working vapor exiting the first cooling load evaporator111may enter the low stage compressor112. The compression of the low stage working vapor may be through a single compressor. Alternatively, one or more compressors may be employed in the thermal system1. Compressors may virtually include any type of compressor capable of capacity and pressure control, such as oil-flooded screw compressors, reciprocating or centrifugal compressors.

The low stage compressor112may compress the low stage working vapor, thereby increasing the pressure and the temperature of the low stage working vapor. The compressed low stage working vapor may exit the low stage compressor112and then circulate to the cascade condenser130.

In the cascade condenser130, the low stage working vapor may be condensed and liquefied when heat is removed, and may completely or in part return to the fluid form. The low stage working fluid may circulate through the cascade condenser130and further to the low stage expansion device113.

The cascade condenser130may be further connected to the high stage loop120. The high stage loop120may process a high stage working fluid. The high stage working fluid may include a refrigerant. In one aspect, the high stage working fluid may be any suitable working fluid for a particular application of the system, such as flammability, toxicity, or the like. In some aspects, the high stage working fluid may include fluoride. In various aspects, the high stage working fluid may include fluoroolefins.

The high stage loop120may include a high stage compressor121and a high stage condenser122. While circulating through cascade condenser130, the high stage working fluid may be evaporated by absorbing heat from the low stage working vapor being liquefied and may form a high stage working vapor. The high stage working vapor may circulate through the cascade condenser130and further to the high stage compressor121.

The high stage compressor121may compress the high stage working vapor, thereby increasing the pressure and the temperature of the high stage working vapor. The compressed high stage working vapor may circulate to the high stage condenser122.

In the high stage condenser122, the high stage working vapor may be condensed and liquefied. The high stage working fluid exiting the high stage condenser122may optionally circulate to the high stage expansion device123that may substantially reduce the pressure and the temperature of the high stage working fluid. The high stage working fluid exiting the high stage expansion device123may circulate to the cascade condenser130.

The cooling rate of the test chamber having the first cooling system may depend on the capacity of the cooling systems in the thermal system I. In one aspect, the cooling rate of the first cooling system100may be 1° C./min or higher. For example, the cooling rate of the first cooling system100may be in a range of from about 1.4° C./min to about 4.5° C./min. The test chamber10may be operated in a temperature range of from about −73° C. to about 200° C. The test chamber10may be configured to control Relative Humidity. For example, the test chamber10may be operated in a humidity range of from about 10% RH to about 90% RH. The first cooling system may have power in various ranges. In one aspect, the first cooling system may have power of 1 HP or higher. In some aspects, the first cooling system may have power in a range of from about 1 HP to about 5 HP. In various aspects, the first cooling system may have 2 HP.

The test chamber may be further connected to the second cooling system200. The second cooling system may have power of 1 HP or higher. In some aspects, the second cooling system may have power in a range of from about 1 HP to about 5 HP. In various aspects, the second cooling system may have 2 HP. Optionally, the power of the second cooling system may be equal to or less than the power of the first cooling system.

The second cooling system200may include a fluid coil201, a thermal storage203, and a thermal storage chiller202. In one aspect, the thermal storage203may be placed outside the test chamber10. In some aspects, the thermal storage203and the thermal storage chiller202may be placed outside the test chamber10. In various aspects, the fluid coil201may be placed inside the test chamber10.

The second working fluid may be a refrigerant. In one aspect, the second working fluid may be any suitable working fluid for a particular application of the system such as flammability, toxicity, or the like. In some aspects, the second working fluid may include fluoride. In various aspects, the second working fluid may include fluoroolefins.

In one aspect, the fluid coil201may be placed inside the test chamber10. The second working fluid from the thermal storage203may enter the fluid coil201. The temperature of the second working fluid may increase by absorbing heat from the ambient air while traveling through the fluid coil201. The heated second working fluid or vapor may circulate to the thermal storage chiller202.

In one aspect, the thermal storage chiller202may be placed outside the test chamber10. The second working fluid may be condensed and cooled and/or liquefied while traveling through the thermal storage chiller202.

The cooled second working fluid exiting the thermal storage chiller202may enter the thermal storage203. In one aspect, the thermal storage203may be placed outside the test chamber10. The operating temperature of the thermal storage may be in a range of from about −75° C. to about 210° C. In various aspects, the thermal storage203may lower the temperature of the second working fluid entering the thermal storage203. For example, the thermal storage203may lower the temperature of the second working fluid entering the thermal storage203by 10° C. or more.

FIG. 3depicts a schematic diagram showing another exemplary thermal system1including the test chamber10according to the disclosure. Similar to the thermal system1described inFIG. 2, the test chamber10may include the first cooling system100with the cascade condenser130. The test chamber10may be further connected to the second cooling system200. The first cooling system100may include the low stage loop110and the high stage loop120. Subsequently, the low stage loop110may include the first cooling load evaporator111, the low stage compressor112, and the low stage expansion device113. The low stage loop110may be connected to the cascade condenser130.

In one aspect, the low stage loop110may have one or more valves such as valves114,115placed in various locations in the low stage loop110. The valves may adjust the amounts of low stage working fluid or vapor circulating through the low stage loop110.

The high stage loop120may have one or more valves such as valves124,125,126placed in various locations in the high stage loop120. The valves may adjust the amounts of high stage working fluid or vapor circulating through the high stage loop120.

The second cooling system200may include a pump204to circulate the second working fluid in the second cooling system200. In one aspect, the pump204may be placed outside the test chamber10. The second working fluid exiting the second thermal storage203may enter the pump204. The second working fluid exiting the pump204may enter the fluid coil201. Optionally, the pump204may include a brine pump. Alternatively, there may be a bypass between the brine pump204and the fluid coil201so that the second working fluid exiting the brine pump204may enter the thermal storage chiller202when the test chamber10does not need additional cooling from the second cooling system200.

In one aspect, the test chamber10may include one or more cooling load evaporators. In some aspects, the test chamber may include at least one cooling load evaporator from the first cooling system and at least one from the second cooling system. The test chamber10including such a plurality of cooling systems may achieve a cooling rate of 10.0° C./min or higher.

The thermal system1may include a controller500. The controller500may control temperature and/or other operating conditions of the thermal system1so that the temperature of the test chamber10can remain in a determined range. The thermal system1may further include one more of temperature sensors301,302and a power unit400. The controller500; and the sensors301,302may be connected to the first cooling system100and the second cooling system200.

One or more of sensors such as sensors301,302may be placed in various locations such as the test chamber10, and the cooling systems100,200. The sensors301,302may monitor the temperatures and/or operating conditions of the designated places and communicate the obtained temperature and/or operating conditions to the controller500. The power unit400may deliver power to the test chamber10and any affiliated units thereof such as the first cooling system100, the second cooling system200and the controller500. Operation of the power unit400may be in turn controlled by the controller500.

The controller500may include a general purpose computer or specialty computer or programmable circuit board or other circuitry. In one aspect, the controller500may include a processor which may be a computer including a central processing unit (CPU), an application specific integrated circuit (ASIC), a microprocessor, microcontroller, a field programmable gate array (FPGA), complex programmable logic device (CPLD), or other suitable processor or processing device, with associated memory or programming, for controlling the operation of test chamber and any affiliated units thereof. The controller500may be connected to and control the valves,114,115,124,125,126,205,206,207,208of the cooling systems

Within the controller500, the individual control signals from the sensors301,302are used to determine/calculate optimal process threshold values. Such threshold values may be used to specify bypass, speed, slide valve position and the like. In one aspect, the threshold values may be used to adjust the quantity of stored working fluid and the operating temperature and pressure of the cooling systems100,200and those of the test chamber10. In some aspects, the test chamber10may be cooled only with the first cooling system100placed within the test chamber10. Based upon information received from one or more sensors301,302, the controller500at operation may determine, or calculate the optimal threshold values of the test chamber10. If the test chamber10does not achieve the optimal threshold values, for example, such as a target temperature and a target cooling rate, only with the first cooling system, the controller500may activate the second cooling system200during the operation of the first cooling system100.

FIG. 4depicts a schematic chart showing exemplary operation steps of the controller500. In step501, the controller500may determine if the thermal storage203is needed during the off cooling cycle and proceed to step502to enable the thermal storage203if necessary. In one aspect, the thermal storage203may be enabled in a thermal program where a temperature profile including heating and soaking is long enough for the thermal storage203to store a desired cooling capacity (step503). In some aspects, the thermal storage203may be enabled when the thermal program requires a fast temperature pull down rate (step504). For example, the controller500may be configured to allow the thermal storage203to reach the peak storage capacity and pull down the temperature as fast as possible using the first cooling load evaporator111and the fluid coil201. Subsequently, the controller500may activate the thermal program (step505).

FIG. 5depicts another schematic chart showing exemplary operation steps of the controller500. In step511, the controller500may check the test chamber10and proceed to step512to determine the current temperature and the target temperature. Subsequently, the controller500may proceed to step513to activate the first cooling system100, The controller500may further determine the current cooling rate of the test chamber10while operating the first cooling system100as in step514. When the current cooling rate {dot over (T)} of the test chamber10is below {dot over (T)}c where {dot over (T)}c is a threshold cooling rate as shown below,

the controller500may activate the second cooling system200as in step515while operating the first cooling system100.

The controller500may adjust valve positions, speed, or guide vanes to achieve the optimal threshold values. For example, based on the operating temperature and the operating cooling rate, the controller500may proportion one or more of the valves114,115,124,125,126,205,206,207,208connected to the cooling systems on each cooling cycle to achieve a desired temperature or cooling rate in the test chamber10. The valves114,115,124,125,126,205,206,207,208may be of several types including but not limited to thermo-static valves and electrically driven control valves. Optionally, the valves114,115,124,125,126,205,206,207,208may be equipped with local control logic.