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application is using existing fan coils for heating, especially
those previously sized for high water temperatures.
A room-by-room calculation should always be performed
for all radiant oor system in order to determine the
design of the radiation system. Once the heat loss has
been calculated and the decision on ooring material has
been made for each room, the amount of radiant oor
tubing, pipe spacing, water temperature and layout can
be determined, based upon the Btu/h per square foot
requirements.
Radiant oor heating typically allows occupants to
experience the same comfort level with radiant oor
heating at approximately 65°F as with a forced air system
at approximately 70°F. Installers should realize that a
radiant oor system heats objects, not the air. Then,
these objects radiate heat, which heats occupants and
furnishings to an acceptable and comfortable temperature.
Air temperature typically remains near approximately 65°F,
and is typically equal from the oor to the ceiling. Forced
air heating always heats the air, which heats the occupants
and objects. Thus with force air heating, a higher air
temperature is necessary in order to bring occupants
and objects up to the same temperature as in a radiant
heating system. When a radiant oor system is being
designed, equipment sizing can be signi cantly impacted.
Typically, the heat loss for the structure decreases by
10-20% over a forced air heating system application.
However, Bosch encourages the use of load calculations
at actual temperature differences and in ltration rates for
equipment sizing, rather than "rules of thumb."
16.3 Bosch Geothermal Water-to-Water Heat
Pumps and Radiant Floor Heating
Heating and cooling with water is commonly referred to
as hydronics. Water is considered the most practical,
economical and safe heat transfer medium available.
The most popular application for Bosch water-to-water
geothermal heat pumps is likely radiant oor heating.
Some examples are shown (Figure 119).
Bosch water-to-water geothermal heat pumps are an
excellent heat source for framed- oor as well as slab-type
oor heating systems. The low water temperature required
by such oors (usually 95ºF to 110ºF at design load
conditions) allows the Bosch water-to-water geothermal
heat pump to operate with relatively high capacity and
COP. Additionally the mixing device(s) required when
coupling a low temperature oor heating system to a
conventional boiler are no longer required.
Data subject to change
Fig. 119
When considering the use of a Bosch geothermal water-
to-water heat pump attached to a radiant oor heating
array, a suggested guideline is the combination should
provide design heating load output using supply water
temperatures no higher than 120ºF.
Radiant oor heating is considered by many as the ultimate
form of comfort heating for residential applications. In
addition to the advantages of hydronic heating in general,
warm oors provide bene ts that virtually no other system
can match. Unlike many systems that directly heat the
air, radiant oor heating gently warms the surfaces of
objects in the room as well as the air itself. The warm
surfaces signi cantly reduce the rate of heat loss from
the occupants, allowing most to feel comfortable at
room temperatures 3 to 5 degrees lower than with other
methods of heating.
Bosch water-to-water geothermal heat pumps can be
utilized for hydronic heating during the winter months,
as well as for superior heat rejection during summer
months. These water-to-water geothermal heat pumps
extract low temperature heat from closed-loop ground
heat exchangers, ponds or lakes, or from open-loop
groundwater supply wells, in the winter. They reject
heat from the structure to the closed-loop ground heat
exchanger, pond or lake, or open-loop groundwater
rejection well (or other acceptable rejection site), in the
summer.
Applications Manual
Bosch Thermotechnology Corp.
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