Refrigeration – Reversible – i.e. – heat pump – With flow control or compressor details
Reexamination Certificate
2000-10-06
2001-11-27
Doerrler, William (Department: 3744)
Refrigeration
Reversible, i.e., heat pump
With flow control or compressor details
C062S504000, C062S524000, C062S525000
Reexamination Certificate
active
06321558
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention generally pertains to refrigerant systems and more specifically to refrigerant systems that provide a reheat function in a cooling mode.
2. Description of Related Art
Refrigerant systems operating in a normal cooling mode typically have a refrigerant evaporator that cools a stream of air that is delivered to a room or some other comfort zone. Once the room's temperature (i.e., dry bulb temperature) reaches its target temperature, the refrigerant system may stop running. At times, however, this may leave the room uncomfortably humid. Thus, in some cases, the system may continue operating to reduce the humidity even after the sensible cooling demand of the room has been met.
To avoid over cooling the room in such cases, a heater downstream of the evaporator can be added to reheat the air after the evaporator cools and removes moisture from the air. Operating a refrigerant system in such a manner can be referred to as operating in a reheat cooling mode. In a reheat cooling mode, a refrigerant system can deliver relatively dry air to a room at a temperature close to its target temperature.
Often the heater is an electric coil, which effectively reheats the air, but wastes electrical energy. As an alternative to electric heat, a refrigerant condenser conveying hot refrigerant can possibly reheat the air. However, such an approach may create problems when the refrigerant system operates in modes other than the reheat cooling mode.
For example, when a refrigerant system with a reheat refrigerant condenser operates in a normal cooling mode without reheat, the inactive reheat condenser may flood with liquid refrigerant. The flooding may starve the rest of the system of its proper charge of refrigerant, thus reducing the system's overall efficiency in the normal cooling mode. Likewise, an inactive reheat condenser may flood and starve the rest of a refrigerant system when the system is operating in a heating mode to heat the comfort zone.
SUMMARY OF THE INVENTION
To provide a refrigerant system with a reheat cooling mode, it is an object of the invention to provide the system with an additional refrigerant condenser, which reheats the air that has been previously cooled by the system's evaporator.
Another object of the invention is to vent a reheat heat exchanger to an evaporator of a refrigerant system that is operating in a normal cooling mode, thereby preventing the reheat heat exchanger from flooding with liquid refrigerant.
Another object of the invention is to vent a reheat heat exchanger to an evaporator of a refrigerant system that is operating in a heating mode, thereby preventing the reheat heat exchanger from flooding with liquid refrigerant.
Yet another object is to use a flow restriction to vent a reheat heat exchanger to an evaporator of a refrigerant system, whereby additional cooling is achieved as the refrigerant expands upon passing through the flow restriction.
A further object of the invention is to provide a valve system that selectively reconfigures a refrigerant system in a normal cooling mode, a reheat cooling mode, and a heating mode.
A still further object of the invention is to split the flow of refrigerant flowing from a reheat condenser into a major portion and a minor portion of refrigerant, wherein the major portion is directed toward a water-cooled condenser to expel an appreciable amount of heat to the water, whereby a refrigerant system operating in a reheat cooling mode can still provide an appreciable amount of latent cooling.
Another object is to provide a refrigerant system with a check valve that allows deactivating a reheat heat exchanger when the system is operating in a normal cooling mode.
Another object is to provide a refrigerant system with a check valve that allows deactivating a reheat heat exchanger when the system is operating in a heating mode.
Yet, another object of the invention is to take the refrigerant discharging from a secondary heat exchanger and divide the refrigerant into two portions with one having a higher concentration of liquid than the other, so that the liquid portion can be directly flashed into an evaporator without having to first pass through a condenser.
These and other objects of the invention are provided by a refrigerant system that includes an evaporator for cooling air and a reheat heat exchanger that reheats the air in a reheat cooling mode. The reheat heat exchanger actively heats the air in the reheat cooling mode, but is relatively inactive in a normal cooling mode. In the normal cooling mode, a flow restriction vents the inactive reheat heat exchanger to the evaporator to help prevent the reheat heat exchanger from flooding with liquid refrigerant.
The present invention provides a refrigerant system using a refrigerant to transfer heat between air and a fluid, wherein the air is supplied to a comfort zone. The system comprises: a compressor adapted to compress and discharge the refrigerant; a fluid heat exchanger having a refrigerant passageway in heat transfer relationship with the fluid; a primary heat exchanger that places the refrigerant in heat transfer relationship with the air; a secondary heat exchanger exposed to the air; a primary refrigerant flow restriction that helps couple the primary heat exchanger to the fluid heat exchanger; a secondary refrigerant flow restriction that helps couple the primary heat exchanger to the secondary heat exchanger; and a flow divider having an inlet, a first outlet and a second outlet. The inlet is adapted to receive the refrigerant discharged from secondary heat exchanger, the first outlet is adapted to discharge a first portion of the refrigerant toward the primary heat exchanger and the second outlet is adapted to discharge a second portion of the refrigerant toward the refrigerant passageway of the fluid heat exchanger. The first portion has a greater concentration of refrigerant in a liquid state than the second portion.
The present invention also provides a refrigerant system using a refrigerant to transfer heat between air and a fluid, wherein the air is supplied to a comfort zone. The system comprises a compressor adapted to compress and discharge the refrigerant; a fluid heat exchanger having a refrigerant passageway in heat transfer relationship with the fluid; a primary heat exchanger that places the refrigerant in heat transfer relationship with the air; a secondary heat exchanger exposed to the air; a primary refrigerant flow restriction that couples the primary heat exchanger to the fluid heat exchanger; a secondary refrigerant flow restriction that couples the primary heat exchanger to the secondary heat exchanger; and a reheat valve. The reheat valve is selectively operable in a normal mode and a reheat cooling mode and has a first outlet in refrigerant communication with the refrigerant passageway of the fluid heat exchanger, a second outlet in refrigerant communication with the secondary heat exchanger, and an inlet situated to receive compressed refrigerant from the compressor. With the reheat valve in the normal mode most of the refrigerant discharged from the compressor bypasses the secondary heat exchanger and the secondary refrigerant flow restriction and passes in series through the inlet of the reheat valve, the first outlet, the refrigerant passageway of the fluid heat exchanger, the primary refrigerant flow restriction, and the primary heat exchanger. With the reheat valve in the reheat cooling mode most of the refrigerant discharged from the compressor bypasses the secondary refrigerant flow restriction and passes in series through the inlet of the reheat valve, the second outlet, the secondary heat exchanger, the fluid heat exchanger, the primary refrigerant flow restriction, and the primary heat exchanger.
The present invention further provides a refrigerant system using a refrigerant to transfer heat between air and a fluid, wherein the air is supplied to a comfort zone. The system comprises a compressor adapted to compress and discharge the
American Standard International Inc.
Beres William J.
Doerrler William
O'Driscoll William
Shulman Mark
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