Dehumidification >> How To Pick A Dehumidifier

This unit will be used to illustrate all of How To Pick A Dehumidifier the recuperative precooling and reheating concepts. It will graphically show that they perform the same function—even though some require specific physical arrangements.

 
 HEAT-PIPE RUN-AROUND PRECOOLING, How To Pick A Dehumidifier REHEATING Although their use in dehumidification is relatively new, heat pipes have been around for decades. A heat pipe is a heat-transfer assembly that includes a heating section connected to and located slightly above a cooling section.

 In Figure 5, the lower cooling section is upstream from the main cooling coil, while the upper heating section is downstream. This allows for a transfer of sensible heat from the warm, humid incoming air to the cold exiting air, which reduces or How To Pick A Dehumidifier eliminates the external reheat energy requirement. The air leaving the unit is warmer and dryer.

 The arrangement of the equipment room and the entering- and leaving-air duct work poses a major challenge to the side-by-side placement of the joined sections of the heat pipe or How To Pick A Dehumidifier an alternate arrangement with the cooling section below the heating section. The lines between the two coils (and the coil headers if exposed to ambient air) must be insulated to prevent external heat transfer.

 Advantages. The main advantages of heat pipes are: • They have no moving parts. • They have no external connections to either water circuits or electricity. • They are How To Pick A Dehumidifier not susceptible to damage from freezing conditions. • They do not require a compression tank.

 Disadvantages. Disadvantages of heat pipes are: • The coils are more expensive than are run-around coils because they are not mass-produced and each of the many refrigeration circuits in heat pipes must be individually evacuated and How To Pick A Dehumidifier charged with a critical amount of a volatile refrigerant. • ARI-certified ratings are not available. • Selection is made only by the manufacturer. • Control is difficult and expensive (however, in many applications, control of the run-around coil or heatpipe system is not required). • The physical arrangement of the coils must enable gravity drainage or capillary transfer of the condensed refrigerant from the heating coil to the precooling coil. • Multiple reheat coils are not available.

 Ã‚• If heat pipes are installed in an AHU, How To Pick A Dehumidifier then the AHU’s coil section must be shipped to the heat-pipe manufacturer or the two heat-pipe sections must be joined by field-installed piping, with each circuit tested, evacuated, and charged by the manufacturer at the job site. (For small AHUs, a precharged wrap-around heat pipe is available.)

 AIR-TO-AIR FLAT-PLATE HEAT EXCHANGERS Flat-plate heat exchangers consist of a series of flat or How To Pick A Dehumidifier nearly flat heatexchange surfaces arranged in such a way that alternating air passages are connected to one air stream with remaining passages connected to the second air stream. Figure 6 illustrates the recuperative application of the air-to-air flat-plate heat exchanger. The precooling section should be sloped in the direction of air flow to a condensate drain.

 Advantages. The main advantages of flat-plate heat exchangers are: • They have no moving parts. • They have no external connection to water circuits, ethylene glycol, refrigerant, How To Pick A Dehumidifier or electricity. • They have no heat-transfer fluids that are subject to freezing.

 Disadvantages. Disadvantages of flat-plate heat exchangers are: • Control is impossible unless bypass dampers are used. • The physical arrangement of How To Pick A Dehumidifier their external components is more restrictive than that of the other recuperative-dehumidification enhancements because of the requirement of alternate air streams in cross-flow or counterflow arrangements. • ARI-certified ratings are not available. • Some leakage or cross flow may occur if the sealant at the edge of plates is not perfect.

 ROTARY-WHEEL HEAT EXCHANGERS The rotary-wheel heat exchanger usually consists of a honeycomb (fluted) aluminum rotor. An 8-in.- wide corrugated layer of aluminum sheet and an 8-in.-wide flat aluminum sheet are wound around a hub to create an 8-in.-deep rotor (depth varies by manufacturer) with diameters up to about 8 ft. The rotor usually is encased in a housing (cassette) that includes seals at the wheel periphery and How To Pick A Dehumidifier at the sectional divider between air streams. The rotor housing is ducted to the two air streams as shown in Figure 7. One half of the rotor picks up heat from the warm air stream. As the rotor rotates at about 20 rpm, this heat is transferred to the cool air stream.

 Advantages.The main advantages of rotary-wheel heat exchangers are: • There is no water, ethylene glycol, How To Pick A Dehumidifier or refrigerant charge. • Control is easy. • They have no heat-transfer fluids that are subject to freezing. 

 Disadvantages. Disadvantages of rotary-wheel heat exchangers are: • A restricted physical arrangement of inlet and outlet air streams. • The requirement of 120-v, How To Pick A Dehumidifier 60-cycle single-phase power to a fractional-hp motor. • ARI-certified ratings are not available. • The media in the rotor may be susceptible to clogging. • Some drive systems have been unreliable or have required high maintenance. • The life of the rotor may be shorter than that of other options. • Leakage between air streams reduces effective air quality and performance. The initial leakage rate may be acceptable; however, the wearing of seals, etc. can result in increased leakage. • Condensation may be detrimental to some types of rotors and media.

 REFRIGERANT LIQUID SUBCOOLING/AIR REHEATING Reheating a cooled air stream using heat from liquid refrigerant en route to a direct-expansion cooling coil is quite desirable from an efficiency standpoint, How To Pick A Dehumidifier as it requires only a single coil to accomplish what the previous arrangements do with two heat-transfer devices. Figure 8 illustrates this dehumidification enhancement. The temperature of the refrigerant liquid supplied to a direct-expansion coil often is in the 90- to 115-F range.

 The reheat coil uses this warm liquid to reheat the cold air stream while simultaneously subcooling the liquid refrigerant. The subcooled liquid refrigerant then enters the directexpansion coil and, How To Pick A Dehumidifier because it is subcooled, increases the latent and total capacity of the cooling coil. Figure 9 shows compressor-condenser capacity with and without subcooling as well as evaporator-cooling-coil capacity.

How To Clean Up Raw Sewage In A Basement

Water from precipitation is not always the only source Basement Drying How To Clean Up Raw Sewage In A Basement of moisture. Urban development usually includes a centralized public water supply for the development. If the supply were through private domestic wells, then waterline leaks would be easy to identify. Simply turn off all the fauc  read more..

How To Begin To Declutter A Hoarding Situation

Too much clutter and dirt in your home can cause germs, pests, and contaminants to collect, which can make your family sick. A dirty home can put your family at risk for poisonings and injuries, and can cause health problems like asthma."Keeping a home clean includes controlling the source, creating  read more..

How To Use Sandbags To Prevent Flooding

It is dangerous to go back intoyour home because the flood mayhave caused structural, electrical, Flood Damage How To Use Sandbags To Prevent Flooding and other hazards. After you havemade things safe, take steps to protect your home and contents fromfurther damage.

Most of the information in thissection assumes that t  read more..

How To Cure Hoarding

We are anticipating a significant and sustained increase in the number of hoarding cases that will be brought to the attention of community agencies. The increase is in part the result of greater public awareness of the hoarding phenomena through various media efforts and Hoarding How To Cure Hoarding the overall   read more..

Tenants Right About Mold In An Apartment

The meaning of mold sampling results that are in CFU/m2 and CFU/m3 Sampling results for viable (living) microorganisms are presented as concentrations, and the units used will vary depending on the sample collection methods. Air sampling results are reported as Mold Remediation Tenants Right About Mold In An Apartment colony-forming units pe  read more..

Wet Crawl Space Dehumidification Vs Ventilation

While the kiln described in this publication is designed for simple operation, you will still need to closely monitor the drying process. Monitoring the moisture loss and quality of the wood during the drying process will help you maximize the efficiency of the kiln. Simply explained, when drying lu  read more..

Termites And Pest Control

PESTS SEEK PLACES TO LIVE that satisfy basic needs for air, moisture, food, and shelter. The best way to control pests is to try to prevent them from entering your home or garden in the first place. You can do this by removing the elements that they need to survive.Remove water. All living things, i  read more..

Lead Paint Removal Procedures

The employer shall assure that employees do not enter lunch room facilities or eating areas with protective work clothing or equipment unless surface lead dust has been removed by vacuuming, downdraft booth, or other cleaning method that limits dispersion of lead dust. (5) Hand washing facilities. (  read more..

How To Remove Asbestos Pipe Insulation

Pressure Differential: The design parameters for static pressure differentials between the inside and outside of enclosures typically range from 0.02 to 0.10 inches of water gauge, depending on conditions. All zones inside the enclosure must have less pressure than the ambient pressure outside of th  read more..

How To Help A Hoarder

In some cases, the best option would be to put the property into a receivership under Health & The City would ask the court to appoint a receiver who would take over the property and would have the power to make arrangements for repairs, cleanup, or sale. The receiver would work with the Hoarding How To Help A Hoarder in  read more..