초록 ▼

A test chamber that is capable of operating in a mode where the temperature of the chamber is efficiently cooled without removing a substantial amount of moisture from the air. In one aspect, the test chamber includes a structure defining a work space having air, and a temperature control system (e.

A test chamber that is capable of operating in a mode where the temperature of the chamber is efficiently cooled without removing a substantial amount of moisture from the air. In one aspect, the test chamber includes a structure defining a work space having air, and a temperature control system (e.g., a refrigeration system having a compressor, a condenser, and an evaporator valve). The temperature control system includes a heat exchanger (e.g., an evaporator) positioned to communicate with the air in the work space, a source of cold fluid (e.g., a compressed, condensed, and throttled refrigerant) coupled to the heat exchanger, a source of hot fluid (e.g., compressed refrigerant gas) coupled to the heat exchanger, and a controller for controlling a mixture of cold fluid and hot fluid entering the heat exchanger (e.g., by adjusting a cold fluid valve and/or a hot fluid valve). In order to limit the loss of humidity caused by condensation on the heat exchanger, it is preferred that the controller is programmed such that the temperature of the mixture entering the heat exchanger is controlled to limit a temperature differential between the heat exchanger and the air in the work space.

대표청구항 ▼

1. A test chamber comprising: a structure defining a work space having air; a refrigeration system comprising: a heat exchanger positioned to communicate with the air in the work space; a compressor coupled to the heat exchanger and producing a hot fluid; a condenser coupled to the compressor and pr

1. A test chamber comprising: a structure defining a work space having air; a refrigeration system comprising: a heat exchanger positioned to communicate with the air in the work space; a compressor coupled to the heat exchanger and producing a hot fluid; a condenser coupled to the compressor and producing a liquid; a throttle valve coupled to the condenser and producing a cold fluid; and a controller for controlling a mixture of cold fluid and hot fluid entering the heat exchanger, wherein the controller includes a temperature-humidity mode in which the controller is programmed to control a flow rate of cold fluid mixing with the hot fluid at a first flow rate, and programmed to determine a temperature of air in the test chamber, and if the temperature of air in the test chamber is greater than a desired temperature range, the controller is programmed to increase the flow rate of cold fluid mixing with the hot fluid by a slight increment, said slight increment being designed to control a temperature differential between the mixture and air in the work space in order to control condensation formation on the heat exchanger so as to limit loss of humidity in the air in the work space, to reach a second flow rate that is greater than the first flow rate, programmed to monitor the temperature of air in the test chamber, and programmed to determine whether the temperature of air in the test chamber has decreased, and if the temperature of air in the test chamber has not decreased, the controller is programmed to further increase the flow rate of cold fluid mixing with the hot fluid by a slight increment to reach a third flow rate that is greater than the second flow rate and programmed to continue monitoring the temperature of air in the test chamber, determining if the temperature of air in the test chamber has decreased, and continuing increasing the flow rate of the cold fluid mixing with the hot fluid by a slight increment if the temperature of air in the test chamber has not decreased until a decrease in temperature is achieved, thereby the controller is controlling a ratio of cold fluid and hot fluid in the mixture to control a temperature differential between the mixture and air in the work space in order to control condensation formation on the heat exchanger. 2. The test chamber as claimed in claim 1, wherein the controller is programmed such that the temperature differential between the mixture and the air in the work space is controlled. 3. The test chamber as claimed in claim 1, wherein the refrigeration system further comprises a cold fluid valve that limits an amount of cold fluid entering the heat exchanger, wherein the controller adjusts the cold fluid valve to control the amount of cold fluid mixing with the hot fluid to control a temperature of the mixture entering the heat exchanger. 4. The test chamber as claimed in claim 3, wherein the controller includes the temperature-humidity mode that is programmed to limit a drop in the temperature of the mixture to thereby limit a temperature differential between the mixture and the air in order to reduce condensation formation on the heat exchanger. 5. The test chamber as claimed in claim 4, wherein the controller further includes a dehumidification mode that is programmed to allow a greater drop in temperature of the mixture to thereby increase a temperature differential between the mixture and the air in order to increase condensation formation on the heat exchanger. 6. The test chamber as claimed in claim 1, wherein the heat exchanger is an evaporator. 7. The test chamber as claimed in claim 6, wherein the cold fluid is a refrigerant. 8. The test chamber as claimed in claim 6, wherein the refrigeration system further comprises a hot fluid line connecting an output of the compressor with an input of the evaporator. 9. The test chamber as claimed in claim 8, wherein the refrigeration system further comprises a hot fluid valve that limits an amount of hot fluid entering the evaporator, wherein the controller adjusts the hot fluid valve to control the amount of hot fluid mixing with the cold fluid exiting the throttle valve to control a temperature of the mixture entering the evaporator. 10. A method of controlling a temperature of air in a test chamber having a temperature control system including a source of cold fluid, a control valve that limits the flow of cold fluid, a source of hot fluid, and a heat exchanger, the method comprising: positioning the heat exchanger in communication with the chamber; flowing the cold fluid toward the heat exchanger at a first flow rate; flowing the hot fluid toward the heat exchanger; simultaneously directing the temperature of air in the test chamber towards a desired temperature range and maintaining a humidity of the air near a desired humidity range by controlling a flow rate of the cold fluid mixing with the hot fluid; mixing the cold fluid with the hot fluid to produce a mixture entering the heat exchanger; and determining the temperature of air in the test chamber and, if the temperature of air in the test chamber is greater than a desired temperature range, performing the following steps: increasing the flow rate of cold fluid mixing with the hot fluid by a slight increment, said slight increment being designed to control a temperature differential between the mixture and air in the chamber in order to control condensation formation on the heat exchanger so as to limit the loss of humidity in the air in the test chamber, to reach a second flow rate that is greater than the first flow rate; monitoring the temperature of air in the test chamber; determining whether the temperature of air in the test chamber has decreased; and if the temperature of air in the test chamber has not decreased, further increasing the flow rate of cold fluid mixing with the hot fluid by a slight increment to reach a third flow rate that is greater than the second flow rate and continuing monitoring the temperature of air in the test chamber, determining if the temperature of air in the test chamber has decreased, and continuing increasing the flow rate of cold fluid mixing with the hot fluid by a slight increment if the temperature of air in the test chamber has not decreased until a decrease in temperature is achieved, thereby controlling a ratio of hot fluid and cold fluid in the mixture to control the temperature differential between the mixture and air in the chamber in order to control condensation formation on the heat exchanger. 11. The method as claimed in claim 10, wherein the test chamber further includes a cold fluid valve, and wherein increasing the flow rate of cold fluid by a slight increment includes adjusting the cold fluid valve to control an amount of cold fluid mixing with the hot fluid to control a temperature of the mixture entering the heat exchanger. 12. The method as claimed in claim 10, wherein flowing a cold fluid comprises: compressing a refrigerant into a superheated vapor;condensing the superheated vapor into saturated or subcooled liquid; andthrottling the liquid, wherein the liquid is the cold fluid. 13. The method as claimed in claim 12, wherein flowing a hot fluid comprises diverting a portion of the superheated vapor toward the heat exchanger, wherein the superheated vapor is the hot fluid. 14. has been amended to read: The method as claimed in claim 13, wherein the test chamber includes a hot fluid valve, and wherein controlling includes adjusting the hot fluid valve to control an amount of hot fluid mixing with the cold fluid to control a temperature of the mixture entering the heat exchanger. 15. A method of controlling a temperature of air in a test chamber having a temperature control system including a source of cold fluid, a source of hot fluid, and a heat exchanger, the method comprising: positioning the heat exchanger in communication with the chamber; flowing the cold fluid toward the heat exchanger; flowing the hot fluid toward the heat exchanger; mixing the cold fluid with the hot fluid to produce a mixture having a ratio of cold fluid to hot fluid; simultaneously directing the temperature of air in the test chamber towards a desired temperature range and maintaining a humidity of the air near a desired humidity range by controlling the ratio; and determining the temperature of air in the test chamber and, if the temperature of air in the test chamber is greater than a desired temperature range, performing the following steps: increasing the ratio by a slight increment, said slight increment being designed to control a temperature differential between the mixture and air in the chamber in order to control condensation formation on the heat exchanger so as to limit the loss of humidity in the air in the test chamber; monitoring the temperature of air in the test chamber; determining whether the temperature of air in the test chamber has decreased; and if the temperature of air in the test chamber has not decreased, further increasing the ratio by a slight increment and continuing monitoring the temperature of air in the test chamber, determining if the temperature of air in the test chamber has decreased, and increasing the ratio by a slight increment if the temperature of air in the test chamber has not decreased until a decrease in temperature is achieved, thereby controlling the ratio to control the temperature differential between the mixture and air in the chamber in order to control condensation formation on the heat exchanger.