Johnson Controls RC Series Engineering Manual page 18

RC SERIES ENGINEERING GUIDE
Application Notes cont.
cooling tower are not required to maintain the loop temperature,
operating and maintenance costs are very low.
Ground-source systems are most applicable in residential and
light commercial buildings where both heating and cooling are
desired, and on larger envelope dominated structures where core
heat recovery will not meet overall heating loads. Both vertical
and horizontally installed closed-loops can be used. The land
space required for the "heat exchangers" is 100-250 sq. ft./ton on
vertical (drilled) installations and 750-1500 sq. ft./ton for horizontal
(trenched) installations. Closed loop heat exchangers can be
located under parking areas or even under the building itself.
On large multi-unit systems, sizing the closed loop heat exchanger
to meet only the net heating loads and assisting cooling loads
with a closed circuit cooling tower may be the most cost effective
choice.
Surface Water - Closed Loop/Ground Source
• Closed Loop/Ground-Source Surface Water Systems also
utilize the stable temperatures of Surface Water to maintain proper
water source temperatures for RC Series extended range heat
pump systems. These systems have all of the advantages of
horizontal and vertical closed loop systems. Due to the extended
loop temperatures, AHRI/ISO 13256-1 Ground Water or Ground
Loop Heat Pumps are required for this application.
In cooling dominated structures, the ground-source surface water
systems can be very cost effective especially where local building
codes require water retention ponds for short term storage of
surface run-off. Sizing requirements for the surface water is a
minimum of 500 sq. ft./ton of surface area at a minimum depth of 8
feet. WaterFumace should be contacted when designs for heating
dominated structures are required.
Plate Heat Exchanger - Closed Loop/Ground Water
• Closed Loop/Ground Water Plate Heat Exchanger
Systems utilize lake, ocean, well water or other water sources to
maintain closed loop water temperatures in multi-unit RC Series
systems. A plate frame heat exchanger isolates the units from any
contaminating effects of the water source, and allows periodic
cleaning of the heat exchanger during off peak hours.
Operation and benefits are similar to those for ground-source
systems. Due to the extended loop temperatures, AHRI/ISO
13256-1 Ground Loop Heat Pumps are required for this application.
Closed loop plate heat exchanger systems are applicable in
commercial, marine, or industrial structures where the many
benefits of a water source heat pump system are desired,
regardless of whether the load is heating or cooling dominated.
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