Ahu Chilled Water Coil

The chilled water enters the ahu fcu and passes through the cooling coil a series of thin pipes where it will absorb the heat of the air blowing across.

Ahu chilled water coil.

The chilled water heats up and the air blowing across it cools down. Dictated by local codes and based on the application each air handler will have a different set of needs including but not limited to fresh air intake humidity control heating filtration and energy recovery. The coils can be either hot water coils chilled water coils or direct expansion coils with the direct expansion coils used as an evaporator coil in a refrigeration circuit. As warm air passes across the coil and comes in contact with the cold surface of the fins heat then transfers from the air to the water flowing through the tubes both cooling and dehumidifying the air.

The chiller produces chilled water and pushes this around the building to air handling units ahu s and fan coil units fcu s etc. The more chilled water flow that flows through the coil the colder the coil gets and the colder the air gets as it passes through the coil. Water cooled chillers are typically located in the basement or lowest floor of a building. Air handlers are part of a system using either a chiller with cooled water or a condensing unit in a direct expansion dx system.

The purpose of the valve is to control the amount of chilled water flow going through the coil. How an air handler works ahu basics. When the chilled water leaves the cooling coil it will now be warmer at around 12 c 53 6 f. Chilled water coils are one of the most common mediums for cooling air.

Comfort is so much more than temperature. That percentage reduction varies based on each coil s unique dimensions but a reliable estimate is a loss of 8 12. Simply piping the coils in the correct manner from the beginning would seem to be the. In some cases we have to dismantle air handling units because of the difficulty in cleaning them.

When cooling air part of the energy is used to separate the water latent heat and the rest is used to lower the air temperature sensible heat. This video depicts a technitian inside of a unit properly cleaning a chill water coil. If you opt to not counter flow a chilled water coil you ll have to reduce the coil s overall performance by a certain percentage. There are some residential air handlers that use either a hot water heater or a boiler for a hot water coil located in the air handling unit.

August 3 2020 december 9 2019 by trey.