Pump And Condensing Gas Boiler - Bosch Geothermal Heat Pumps Applications Manual

Applications Manual
18.3 Bosch Geothermal Water-to-Water Heat

Pump and Condensing Gas Boiler

Integrated System
The system shown (Fig. 151) is a Bosch water-to-
water geothermal heat pump integrated with a Bosch
condensing wall mounted boiler. This system is ideal for
heating markets utilizing hydronic system designs with
medium to low temperature requirements.
It allows for two operating modes:
1. The hydronic heating requirement during the
"shoulder" seasons is provided for by the Water-to-
Water heat pump.
2. The condensing boiler assist during colder periods.
Fig. 151
Bosch Thermotechnology Corp.
Bosch Geothermal Heat Pumps | 121
18.3.1 Bosch Geothermal Water-to-Water Heat Pump
and Condensing Gas Boiler Sequence of Operation
The Bosch Water-to-Water geothermal heat pump provides
the majority of the hydronic energy requirement to the
structure. This energy is stored in a buffer tank sized
according to the size of the Bosch geothermal heat pump.
The structure demands energy from the buffer tank
independently of the operation of the Bosch geothermal
heat pump. The Bosch condensing gas boiler constantly
monitors the current temperature of the buffer tank and
compares this temperature against the system supply
temperature requirement based on outdoor temperature.
As long as the current temperature of the buffer tank
is maintained at or above the necessary system supply
temperature for any given outdoor temperature, the
Bosch condensing gas boiler remains de-energized. If the
temperature of the buffer tank falls below the necessary
temperature requirement, the Bosch condensing gas boiler
will boost the temperature of the buffer tank until the
necessary temperature is achieved.
The Bosch condensing gas boiler in Figure 151 also heats
domestic hot water year round via an indirect domestic hot
water tank using a diverter valve (as shown) to prioritize
domestic hot water.
Data subject to change