Abstract: A refrigeration unit is provided for conditioning air within a refrigerated chamber for housing perishable goods having an improved air exchange device for selectively admitting fresh air into the refrigerated chamber while simultaneously venting air from within the refrigerated chamber. The air exchange device includes a tubular member having a first chamber and a second chamber isolated from first chamber, the first chamber having an inlet in flow communication with a fresh air source and an outlet opening in flow communication with the refrigerated chamber on a suction side of the evaporator, and the second chamber having an inlet in flow communication with the refrigerated chamber in a discharge side of evaporator fan and an outlet opening in flow communication with a space exterior of the refrigerated chamber.

Abstract: A refrigeration unit is provided for conditioning air within a refrigerated chamber for housing perishable goods having an improved air exchange device for selectively admitting fresh air into the refrigerated chamber while simultaneously venting air from within the refrigerated chamber. The air exchange device includes a tubular member having a first chamber and a second chamber isolated from first chamber, the first chamber having an inlet in flow communication with a fresh air source and an outlet opening in flow communication with the refrigerated chamber on a suction side of the evaporator, and the second chamber having an inlet in flow communication with the refrigerated chamber in a discharge side of evaporator fan and an outlet opening in flow communication with a space exterior of the refrigerated chamber.

Abstract: A transport refrigeration system is provided with a variable speed compressor which is operated only in the low capacity perishable range of operation. In this way, the line voltage and frequency power can be used during high capacity operation and a relatively small inverter can be used to provide variable voltage and frequency for the variable speed operation. The variable voltage and frequency can also be provided to a variable speed condenser motor to provide additional condensing capacity during economized operation. It can also be used to provide DC voltage to the compressor for heating purposes.

Abstract: Cooling is provided to the power electronics of a compressor speed control system by way of refrigerant that is routed from a refrigeration system, through the power electronics, and then back to the refrigeration system. The amount of refrigerant flowing to the power electronics is automatically regulated to that needed to cool the electronics since both are substantially proportional to compressor speed. The housing for the power electronics is mounted directly to the side of the compressor, and the compressor is resiliently mounted to a support to thereby provide shock protection to the power electronics.