Refrigeration – Disparate apparatus utilized as heat source or absorber – With vapor compression system
Reexamination Certificate
1998-12-02
2002-02-19
Ford, John K. (Department: 3743)
Refrigeration
Disparate apparatus utilized as heat source or absorber
With vapor compression system
C062S238600, C062S090000, C062S091000, C062S260000, C062S324100, C165S054000, C165S045000, C165S059000, C237S00200B
Reexamination Certificate
active
06347527
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to systems for heating, cooling, humidification and heat recovery ventilation.
DESCRIPTION OF THE PRIOR ART
To date, heating, cooling, humidification and heat recovery ventilation (HRV) have been accomplished by using three or even four separate pieces of equipment. In the situation where four pieces of equipment are used, the common method would include a standard fossil fuel type furnace, a central or window air-to-air type air conditioner, a duct mounted humidifier and a heat recovery ventilator (HRV). When three pieces of equipment are used the heating and cooling system would be one of the components, generally referred to as a geothermal or air-to-air reversible heat pump, while the humidification and heat recovery ventilation would be accomplished with two separate pieces of equipment. In the aforementioned instances the ducting, condensate draining, wiring, fusing and controls are needed for each system individually. There is no way to increase the efficiency with existing systems because they are separate components, so the capital cost and operating efficiencies which could be gained by integration are not available.
The presently available HRV equipment commonly uses a passive cross-flow core or a desiccant wheel core or a Freon-filled direct exchange core, complete with various types of defrost methods. The defrost methods presently available include an electric defrost or various configurations of damper defrost. The electric defrost element which is usually located in the fresh air supply stream generally starts to operate at approximately −5 degrees C. (23 degrees F.). It will then cycle on and off until −15 degrees C. (5 degrees F.) at which time it is on until the temperature warms up to above −15 degrees C. (5 degrees F.). The electric defrost method is obviously inefficient from an operating cost perspective because of the cost to run the electrical elements. The damper type defrost is more widely accepted, as the method of choice. However, there are drawbacks to the existing systems. One method of damper defrost includes closing a damper on the fresh air intake while opening a damper to draw pre-warmed air from the inside of the space. As the pre-warmed air flows through the HRV core, it defrosts the core. Since the exhaust motor still continues to operate, this method causes an unbalanced system, causing a negative pressure in the space while the system is in the defrost mode. Another damper defrost method includes opening a damper within the HRV and re-directing the stale air to the outside to the fresh air intake section. Although this system does not cause the unwanted negative pressure problem, it will cause a problem where the stale exhaust air will be sent to the living area of the space along with all odors common in stale air.
Present day humidifiers use several methods of humidification and controls. The most common type of humidifier includes a return air duct mounted system complete with a humidistat for control. For example, when the humidity level drops to 45% in the winter, the humidistat sends power from an externally mounted transformer to a small, slowly revolving 24V motor which is attached to a wheel wrapped in a sponge-like material (sponge wheel). The sponge wheel is slightly immersed in a water pan. The water is normally taken from a saddle tee located on one of the water lines close to the unit. The sponge wheel soaks up some of the water from the pan as it is revolving. When the pan's water level drops below a pre-set level, then a shut-off float mechanism, mounted to the pan, opens to allow more water into the pan. As the pan fills with water, the float closes and stops, allowing water to flow into the pan. When the return air runs over the sponge wheel, it pulls some of the water into the air stream, thus humidifying the air stream and thereby increasing the humidity level within the space. This system can cause moisture problems which generally result from calcification of the float control and sponge wheel. Control problems and water leakage into the furnace are common within presently offered humidifiers.
It is presently well known that heating and cooling can be accomplished with a geothermal or air-to-air compression-based heating and cooling system, or a reversible, mechanical vapor compression system, hereinafter referred to simply as “heat pumps”. These reversible, mechanical vapor compression systems or heat pump systems have been utilized to accomplish the goal of efficiently heating and cooling together within a unitary reversible system. An air-to-air heat pump absorbs energy and rejects energy to the outdoor air. The application for an air-to-air heat pump in northern climates is limited because when the outdoor air temperature drops below a prescribed level (usually 40 degrees F.), the system cannot pump any further heat out of the air. The cooling side of an air-to-air heat pump does not offer the highest efficiency as achieved with a geothermal heat pump, but can be effective in most temperature ranges. The capital cost of an air-to-air heat pump is lower but again the operating efficiencies suffer in comparison to a geothermal heat pump. Although the capital cost is higher, the popularity of geothermal heat pumps has grown dramatically over the years because of the constant underground temperature and the much higher efficiency levels.
At present, a geothermal heat pump absorbs and rejects energy from underground or fresh water source, in distinctly different ways. It either uses a closed horizontal or vertical ground or lake loop, or it can absorb or reject energy directly from a domestic well or water source on the property. Together, these are hereinafter referred to as “geothermal underground energy sources”.
If the geothermal underground energy source is based on a horizontal closed loop method it includes the use of polyethylene pipe, which is buried in trenches in a horizontal configuration in rows or circuits approximately one foot below the frost level. A closed lake or river loop uses the same polyethylene pipe, but instead of burying the pipe underground as with a horizontal loop, it is simply sunk to the bottom of the. river or lake and adhered to a pre-configured plastic fence matting material. A vertical closed loop involves drilling bore holes down into the ground, all to the same specific depths, inserting polyethylene pipe into the bore holes and connecting them as circuits inside of a trench which links each set of pipes. The circuits are designed to reduce pressure drop to an acceptable level thereby causing the appropriate flow rates. The loop is hooked to two three-way purging valves at the unit. One or two low-voltage pumps are installed in the loop to cause the flow of the liquid within the closed loop. The fluid that is commonly used in a closed loop system includes a mixture of an environment-friendly and government-approved anti-freeze solution along with water. The water and anti-freeze solution is pumped from and to a Freon-to-liquid evaporator/condenser (hereinafter referred to as a “liquid heat exchanger”), by the low voltage pumps at a specified flow rate, causing specific energy absorption or rejection, depending on the mode of operation. The liquid heat exchanger uses Freon within a refrigeration system to pump the energy from the geothermal underground energy source to the indoor Freon-to-air heat exchanger.
If the geothermal energy source is based on an open-well water source, or internal loop in a commercial building water source, the common method of absorbing or rejecting energy is to hook the liquid heat exchanger directly to the available water source. The water is usually pumped in and out of the liquid heat exchanger by the pre-existing water pressure system. In the case of a commercial building which uses an internal closed loop system, the water would be piped and pumped via the pre-existing system. In the case of a residential application in a rural setting the existing well pump would be used to pump
Bailey Louis J.
Haan Ralph
Armstrong R. Craig
Ford John K.
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