US 6,141,979 A · Dual heat exchanger wheels with variable speed

Abstract

A refrigeration system includes a cooling coil and two variable speed heat exchanger wheels (an enthalpy wheel and a sensible wheel) whose rotational speeds are adjusted to control the humidity and temperature of a comfort zone as well as limit the minimum temperature of the cooling coil itself. Each wheel has one half extending across a supply air passageway and another half extending across a return air passageway to transfer heat between the supply air and the return air at a rate that increases with the speed of the wheel. The enthalpy wheel is near the intake and exhaust of outdoor air. The sensible wheel is near a supply air duct and a return air duct associated with the comfort zone. And the cooling coil is disposed in the supply air passageway between the two wheels. In response to a cooling demand, enthalpy wheel speed is adjusted to maintain a minimum coil temperature to avoid coil freeze-up, while sensible wheel speed is adjusted to meet the cooling load. For dehumidification, sensible wheel speed increases to prolong the running time of the system, while enthalpy wheel speed decreases, if necessary, to prevent overcooling the comfort zone.

Claims20

Dependent claims

A refrigeration system responsive to a thermodynamic demand of a comfort zone, comprising:

a housing defining a supply air passageway adapted to convey supply air to said comfort zone and defining a return air passageway adapted to convey return air from said comfort zone;
a first heat exchanger wheel extending into said supply air passageway and said return air passageway and being rotatable at a speed that varies to vary a first heat transfer rate between said supply air and said return air,
a heat exchanger disposed within said supply air passageway and being adapted to cool said supply air by way of a fluid conveyed by said heat exchanger;
a second heat exchanger wheel extending into said supply air passageway and said return air passageway and being rotatable at an upper speed to provide a second heat transfer rate between said supply air and said return air;
a sensor responsive to said thermodynamic demand of said comfort zone;
a transducer responsive to a thermodynamic variable associated with said heat exchanger;
and
a control that adjusts said speed of said first heat exchanger wheel in response to said transducer and turns said second heat exchanger wheel on and off in response to said sensor, whereby said second heat exchanger wheel rotates at said upper speed when said second heat exchanger wheel is turned on and is at rest when turned off.

5 more elements

Dependencies are inferred from the claim text.

Dual heat exchanger wheels with variable speed

Life of this patent

Dual heat exchanger wheels with variable speed

Life of this patent

Abstract

Claims20