Abstract: A method (300) of de-icing a return air intake of a transport refrigeration system is provided. The method comprises using a controller for controlling the refrigeration system; determining (306) when de-icing mode is required; deactivating (308) an evaporator and an evaporator fan of the refrigeration system when de-icing mode is required; activating (310) a heater when de-icing mode is required; adjusting (312) the temperature of the heater to a selected temperature; deactivating (314) the heater when the heater has reached the selected temperature; and permitting (316) the refrigeration system to remain deactivated for a selected time period.

Abstract: A fluid valve is described to help reduce oil sump pressures of a variable speed compressor and a fixed speed compressor working in parallel in a HVAC system. The fluid valve can be a ball valve. Openings of a variable flow through structure of the ball can be configured to elongate along an equator the ball. When the ball rotates along a rotation axis, a size of a variable fluid path formed between the openings can be varied, resulting in a variable pressure drop across the ball. In operation, when the variable speed compressor is operated at different operation speeds, the ball can be rotated to different positions relative to the rotation axis, which may help reduce the pressure differential between the sumps of the variable speed compressor and the fixed speed compressor.

Abstract: A refrigeration system (30) comprises a compressor (36) for driving the refrigerant along a refrigerant flowpath (34) and having a first stage (36A) and a second stage (36B). A first heat exchanger (38) is along the refrigerant flowpath. An intercooler heat exchanger (120) is along the refrigerant flowpath. A second heat exchanger (42) is along the refrigerant flowpath. An additional heat exchanger (170) is along the refrigerant flowpath between the compressor second stage and the first heat exchanger.

Abstract: A method (300) of de-icing a return air intake of a transport refrigeration system is provided. The method comprises using a controller for controlling the refrigeration system; determining (306) when de-icing mode is required; deactivating (308) an evaporator and an evaporator fan of the refrigeration system when de-icing mode is required; activating (310) a heater when de-icing mode is required; adjusting (312) the temperature of the heater to a selected temperature; deactivating (314) the heater when the heater has reached the selected temperature; and permitting (316) the refrigeration system to remain deactivated for a selected time period.

Abstract: A fluid valve is described to help reduce oil sump pressures of a variable speed compressor and a fixed speed compressor working in parallel in a HVAC system. The fluid valve can be a ball valve. Openings of a variable flow through structure of the ball can be configured to elongate along an equator the ball. When the ball rotates along a rotation axis, a size of a variable fluid path formed between the openings can be varied, resulting in a variable pressure drop across the ball. In operation, when the variable speed compressor is operated at different operation speeds, the ball can be rotated to different positions relative to the rotation axis, which may help reduce the pressure differential between the sumps of the variable speed compressor and the fixed speed compressor.

Abstract: A multi-stage low pressure drop muffler for a compressor including a first plate having a hole, a tube attached to the first plate, a plurality of holes disposed around the circumference of the tube, a plurality of tubes extending through a second plate, and an internal ring disposed on the second plate between the center of the second plate and the plurality of tubes. The muffler is designed to muffle a wide range of frequencies, minimize pressure reduction, improve fluid flow, and improve compressor efficiency.