12 Jul 2014

Pre Cool & Save on your airconditioner

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A simple Technology to save you money on air conditioning…

Evaporative cooling lowers air temperature through increasing the moisture content in the air resulting in lower sensible temperature. Evaporative Pre-Condensing cooling is a specific type of evaporative cooling; it is evaporative cooling for the air-conditioning refrigerant condensing cycle. It does not interact at all with the building supply or ventilation air.

Evaporative pre-cooling systems install ahead of the refrigerant condensing system to lower the air temperature on the condenser, reducing refrigerant compressor work, and increasing overall cooling capacity. The compressor effectively performs at the capacity and energy use ratings for the sensible temperature associated with the moisture-saturated air.

Installation Examples:

Installation ExamplesEvaporative pre-cooling systems install ahead of the refrigerant condensing system to lower the air temperature on the condenser, reducing work required by the refrigerant compressor and increasing overall cooling capacity. The compressor effectively operates at the capacity and energy use values for the dry bulb temperature associated with the sensible temperature of the air after it has been saturated with water.

Types

Most evaporative pre-cooling systems are aftermarket, bolt-on  devices. These systems adapt toexisting types of refrigerant based, direct expansion (DX) condensing and compression systems. Third party bolt-on systems are commonly available in two types. Evaporative pre-condensing cooling systems can also be provided as an OEM feature on new DX equipment.

Once-Through Systems

These systems provide a saturated membrane and spray mist upstream of the condenser coil and fan.  The system evaporates close to 100 percent of the membrane moisture with little to no residual water below the membrane. No mist or spray touches the condenser coils. The measure uses a high efficiency membrane to hold moisture provided by micro sprayers located in the frameA logic controller sprays the precise amount of water to minimize water use and prevent water draining on the roof. For some manufacturers no drain is required. Additionally, the added screens and membrane provide an air filter for solid particulate that otherwise would attach to the condensing coils.

Key Characteristics

  • Temperature and humidity sensors as well as compressor duty cycle control spray and water flow.
  • Misting provides efficient evaporative flash cooling with the use of a thinner saturation membrane.
  • Less water may be used due to regulating the amount of water spray according to ambient air evaporation capacity.

Once-Through SystemsOnce-Through SystemsOnce-Through Systems

Recirculation Systems

These systems typically operate by flowing water over/through a saturation membrane with a water collection sump located below the membrane.  Water floods the membrane and evaporates by air pulled by the condenser fan. The water sump includes a recirculation pump to supplement the water flow.  The sump is regularly drained to limit the build-up of solid materials.

Key Characteristics:

  • Water flow is controlled by compressor on/off cycle
  • Typically 4-6” thick saturation membrane
  • Not as water efficient due to excess membrane saturation and periodic sump purge
  • Requires circulation pumping

A simple Technology to save you money on air conditioning…

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