Question:
I have head the words "chilled water" used in reference to commercial
air conditioning systems. Does this mean that water can be used to
cool air below the dew point in a residential system?
I am wondering whether a single water to water heat pump could be
perform the following functions:
1. water to water: Radiant floor heating + domestic hot water
2. water to air: Forced air heating via a water coil in a fan unit
3. water to air: Forced air cooling via a water coil in a fan unit
#1 and #2 would neeed to be able to work at the same time if
thermostats called for both hot water and hot air.
Answer:
Chilled water is commonly used in commercial air conditioning systems.
Water is typically chilled to 40-45°F. Fan coils are designed to use this
water temp. to cool & dehumidify effectively. Systems are in place where
the heat taken from one part of the building is rejected directly into the
hot water heating system (either through radiant floor or fan coil units)
In fact, the Rochester Public Utilities Bldg in Rochester Minn. has had in
operation a system which uses water-water heat pumps to create ice in an
ice storage bank during off peak times (when utility rates are low) while
at the same time heating the building. In the day time, when cooling is
needed, water is chilled by the ice storage and circulated through fan
coils to cool the building at virtually no cost. A geothermal earth loop
is used as an alternate heat source when the ice storage is satisfied, and
a place to reject heat to when the building is satisfied. Water-water
heat pumps are available with a "desuperheater" to provide domestic hot
water whenever the compressor is running, or even with an alternate
condensor for dom. hot water as a third alternative to reject heat to when
needed.
