Dehumidification Pays Dividends
The patented Hy-Dry (TM) System
Theory of the Hy-Dry (TM) System
Hy-Save Inc. addressed these two components of the dehumidification process by utilizing the LPA (Liquid Pressure Amplification) Technology to pump the liquid refrigerant through a subcool/reheat coil placed downstream from the evaporator (Figure 2). In this manner, liquid refrigerant is deeply subcooled on it's way to the expansion valve (TXV), resulting in a dramatic improvement in evaporator performance and moisture removal. At the same time, the heat removed from the liquid refrigerant is used to reheat the supply air stream which reduces the relative humidity of the air delivered. Low dew point subcooling/reheat coils have in fact been used for years, but only through the use of the LPA technology to overcome the pressure losses through the liquid line and subcool/reheat coil can this be accomplished without a significant loss in capacity.
First let us look at a pressure enthalpy chart (Figure 1) to see what is happening. For this analysis, we will use the standard 105 degree condensing temperature with the same liquid temperature. Depending on the size of the Hy- Dry (TM) coil, liquid should be able to be sub cooled to within 5 to 8 degree F of the air temperature leaving the evaporator. As a rule, this will gain 0.5% capacity increase for each degree of subcooling, and that capacity increase is clearly outlined on the pressure enthalpy chart. As an example, with 60 degree F leaving air, we should be able to subcool the liquid to 68 degree F. With 105 degree F normal liquid temperature, this would be 37 degree F of subcooling, or a capacity increase of 18.5% (this capacity increases is a direct result of the cooler refrigerant).
As the liquid exits the TXV, a certain portion will boil off just to cool the refrigerant to the saturation temperature. This flash off of liquid only cools the refrigerant and does not remove heat in the evaporator. However, the compressor sees it as additional work and must still compress this vapor. The colder the entering refrigerant, the less excess vapor there is to be recompressed. In addition, as can be seen on a pressure enthalpy chart, the percent quality of the refrigerant improves from about 72% liquid without subcooling to about 83% liquid with the Hy-Dry (TM) coil in operation. So that is how subcooling helps remove more moisture from the air and the next step is reheat.
Computer rooms and other applications that require strict relative humidity control have long used reheat. Essentially, the air is over cooled to remove moisture and then reheated to raise the temperature back to the set point. This process of reheating also provides a lower relative humidity air. This technique is energy intensive since added cooling is required and energy to reheat the air is required, one might say a lose-lose energy situation. With Hy-Dry (TM) it is a win-win energy situation. The heat is removed from the refrigerant (subcooling = win). and is used for "free" reheating (lower relative humidity = win). No extra or external energy is used. So from all the above it should be clear why Hy-Dry (TM) combines win-win factors to improve overall system efficiency.
THE HY-DRY (TM) SYSTEM PUT TO THE TEST
THE HY-DRY (TM) SYSTEM PUT TO WORK IN THE ETL TESTING LABORATORIES
The manufacturer of this line of AC equipment conducted test of Hy-Dry (TM) at their facilities prior to sending it out for certification. These test were conducted with 35% relative humidity entering the evaporator. Under these conditions over 200% more moisture was removed when compared to the same system without the Hy-Dry (TM) system operating.
THE HY-DRY (TM) SYSTEM PUT TO WORK IN THE FIELD
At the Florida Department of Health and Rehabilitative Services (HRS) Crystal lake Service Center in Pompano Beach, Florida; six brand new Trane 30 Ton and one 40 Ton split package units were retrofitted with the Hy-Save LPA(TM), Liquid Injection, and Hy-Dry (TM) Technology. During ambient conditions of 89 degrees F dry Bulb and 83% RH, the monitoring showed a 32% reduction in relative humidity inside the building from 66% to 45% relative humidity (RH).
An installation at the North Marion High School in Sparr Florida, showed a 67% increase in total cooling BTU's, a 49.7% decrease in KW per Ton, and a 20% overall reduction in RH, all of which was accomplished under ambient conditions that went from 35% RH during the monitoring before retrofit to 90% RH after installation. Monitoring by the local Utility, Florida Power Corp. showed a decrease in KW demand of 22%.
BENEFITS OF THE HY-DRY (TM) SYSTEM INDOOR AIR QUALITY
COMFORT FOR BUILDING OCCUPANTS
By-Line: John Bergfeld is on the Board of Directors of APEC (Association of Professional Energy Consultant) which has a goal of "Bridging the Technology Gap" by providing technology transfers of information.
THE HY-DRY (TM) SYSTEM IS THE SUPERIOR SOLUTION TO INDOOR AIR QUALITY AND EFFICIENCY IN AIR CONDITIONING/REFRIGERATION APPLICATIONS !