Abstract: Condensate accumulating in the incoming outside air flow passages of a heat exchanger is fed back into the exhaust flow passages of the heat exchanger to provide improved heat transfer in the heat exchanger, and to avoid the necessity for drainage of the condensate from the heat exchanger. The heat exchanger includes a plastic multi-tube panel core and a solid plastic housing, with opposed-flow heat exchange and inlet-outlet extensions from only one side of the core.

Abstract: The heat exchanger is made economically by pressure-forming cavities in relatively thick thermo-plastic panels, interleaving them with other thermo-plastic panels having separate gas flow conduit structures, and securing the panels together. Preferably, the heat exchanger is an opposed-flow-heat-exchanger giving improved heat-transfer efficiency.

Abstract: The heat exchanger is made economically by using thermoplastic sheets with hollow tubes and spacers between the sheets and fusing the edges of the sheets together to form an integral housing. Preferably, the heat exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: Condensate accumulating in the incoming outside air flow passages of a heat exchanger is fed back into the exhaust flow passages of the heat exchanger to provide improved heat transfer in the heat exchanger, and to avoid the necessity for drainage of the condensate from the heat exchanger. The heat exchanger includes a plastic multi-tube panel core and a solid plastic housing, with opposed-flow heat exchange and inlet-outlet extensions from only one side of the core.

Abstract: The dehumidifier uses an all-plastic air-to-air heat exchanger together with an integral chiller to cool the incoming air to remove water vapor, and then exchange heat with incoming air to cool the incoming air and re-heat the outgoing air. The degree of dehumidification and the temperature of the outgoing air can be controlled by varying the speed of a variable speed fan so as to provide varying degrees of cooling as well as dehumidification. A programmable controller can be used to operate the dehumidifier automatically, either together with a humidistat and thermostat, or in accordance with a predetermined time profile for the conditioned space.

Abstract: The ventilating system includes evaporative cooling of the exhaust air before it enters a heat exchanger to cool incoming fresh outside air. A suction fan pulls exhaust air through the heat exchanger and, in combination with a flow restrictor, reduces the pressure on the exhaust air and augments the evaporative cooling. The use of a pusher fan to force outside air through the heat exchanger ensures that any leakage in the heat-exchanger results in outside air entering exhaust air and minimizing the chances of contamination by leaking exhaust air into the incoming fresh air. The heat exchanger is made economically by heat-forming cavities in relatively thick thermo-plastic sheets, interleaving them with other thermo-plastic sheets having separate gas flow conduit structures, and securing the sheets together. Preferably, the heat-exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: The ventilator system and method use a heat exchanger to selectively transfer heat between fresh outside air entering and exhaust air leaving an enclosed space whenever energy can be recovered from the exhaust air by doing so. The system uses a microprocessor-based controller which stores one or more profiles indicating the time-varying needs of the enclosed space for heating and cooling. The transfer of heat between the exhaust and fresh air is reduced or eliminated simply by reducing the speed of or stopping the exhaust air handler while the fresh air handler continues to run. Evaporative cooling for the exhaust air can be provided, and an all-plastic plate type heat exchanger preferably is used, together with an air handler at the exhaust outlet of the heat exchanger to pull exhaust air through the heat exchanger.

Abstract: The heat exchanger is made economically by using thermoplastic sheets with hollow tubes and spacers between the sheets and fusing the edges of the sheets together to form an integral housing. Preferably, the heat exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: The ventilating system includes evaporative cooling of the exhaust air before it enters a heat exchanger to cool incoming fresh outside air. A suction fan pulls exhaust air through the heat exchanger and, in combination with a flow restrictor, reduces the pressure on the exhaust air and augments the evaporative cooling. The use of a pusher fan to force outside air through the heat exchanger ensures that any leakage in the heat-exchanger results in outside air entering exhaust air and minimizing the chances of contamination by leaking exhaust air into the incoming fresh air.

Abstract: The heat exchanger is made economically by using thermoplastic sheets with hollow tubes and spacers between the sheets and fusing the edges of the sheets together to form an integral housing. Preferably, the heat exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: The ventilating system includes evaporative cooling of the exhaust air before it enters a heat exchanger to cool incoming fresh outside air. A suction fan pulls exhaust air through the heat exchanger and, in combination with a flow restrictor, reduces the pressure on the exhaust air and augments the evaporative cooling. The use of a pusher fan to force outside air through the heat exchanger ensures that any leakage in the heat-exchanger results in outside air entering exhaust air and minimizing the chances of contamination by leaking exhaust air into the incoming fresh air. The heat exchanger is made economically by heat-forming cavities in relatively thick thermo-plastic sheets, interleaving them with other thermoplastic sheets having separate gas flow conduit structures, and securing the sheets together. Preferably, the heat-exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: The ventilating system includes evaporative cooling of the exhaust air before it enters a heat exchanger to cool incoming fresh outside air. A suction fan pulls exhaust air through the heat exchanger and, in combination with a flow restrictor, reduces the pressure on the exhaust air and augments the evaporative cooling. The use of a pusher fan to force outside air through the heat exchanger ensures that any leakage in the heat-exchanger results in outside air entering exhaust air and minimizing the chances of contamination by leaking exhaust air into the incoming fresh air. The heat exchanger is made economically by heat-forming cavities in relatively thick thermo-plastic sheets, interleaving them with other thermo-plastic sheets having separate gas flow conduit structures, and securing the sheets together. Preferably, the heat-exchanger is an opposed-flow heat-exchanger giving improved heat-transfer efficiency.

Abstract: The ventilator system and method use a isolating heat exchanger to selectively transfer heat between exhaust air leaving an enclosed space and outside air entering the enclosed space. The system operates in three basic modes, under the control of a microprocessor-based controller which is responsive to the temperatures inside and outside of the enclosed space. In the heating mode, heat is transferred from the exhaust air to the outside air when the enclosed space requires heating. In the cooling mode, heat is transferred from the outside air to the exhaust air when the outside air temperature is higher than that in the enclosed space. In the supplemental cooling mode, heat transfer between the exhaust and outside air is reduced or eliminated when the outside air temperature is below the desired temperature in the enclosed space and cooling is required. In the heating mode, the heat exchanger is selectively heated when necessary to defrost it.

Abstract: The ventilator system and method use a isolating heat exchanger to selectively transfer heat between exhaust air leaving an enclosed space and outside air entering the enclosed space. The system operates in three basic modes, under the control of a microprocessor-based controller which is responsive to the temperatures inside and outside of the enclosed space. In the heating mode, heat is transferred from the exhaust air to the outside air when the enclosed space requires heating. In the cooling mode, heat is transferred from the outside air to the exhaust air when the outside air temperature is higher than that in the enclosed space. In the supplemental cooling mode, heat transfer between the exhaust and outside air is reduced or eliminated when the outside air temperature is below the desired temperature in the enclosed space and cooling is required. In the heating mode, the heat exchanger is selectively heated when necessary to defrost it.