Oilon Geopro RE, Operation Manual

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RE010070948EN 6/23
2.1. RE ground source heat pump operation principle
1. Vaporiser 6. Subcooler buffer tank
2. Compressor, de-superheating, option 7. Warm water
3. Condenser 8. HC 1 heating circuit
4. Sub cooler, option 9. Cold water
5. Superheating buffer tank
Image2. RE ground source heat pump operation principle.
RE ground source heat pump standard model does not include super heater exchanger or
subcooler. They can be ordered separately as option.
Subcooler capacity can be max. 10 % of total capacity, so it cannot be used to warm up large
areas. It can be used for heating in location with low temperature such as swimming pool,
terrace or garage. However, utilising subcooler capacity is cost-effective. It does not increase
compressor input, which causes slight COP improvement.
RE pump is always connected to separate buffer tank or buffer tanks. Domestic hot water is
warmed up in domestic hot water loops in buffer tank. Preheating loop can be located in the
middle of the same buffer tank or in another buffer tank. Rest of the heating is carried out by
loop in the upper part of the buffer tank or loop in separate domestic hot water buffer tank.
2.2. Collecting heat
RE ground source heat pump’s heat source is usually a drilled well. The number and depth of
wells depend on heating demand. Soil or waters can also be used as heat source. Heat is
collected from soil using horizontal piping in 1…1,2 m depth. When using waters the piping is
anchored to the bottom. Yet RE pump heating demand is so large that usually drilled well is
used as heat source.
Heat collector piping material is normal plastic water supply pipe. Circulating fluid is anti-freeze
mixture of industrial alcohol (30 %) and water (70 %). In some cases also potassium calcium
formiate solution or betaine based solution can be used.
Ground circuit fluid warms up about 3 degrees during circulation. Collected heat is used to
vaporise refrigerant in heat pump unit.
Horizontal piping requires applicable soil type and sufficient land area for piping. Applicable soil
types are fine grained and most, such as clay or silt.
Drilled well is suitable for all locations except locations where solid rock goes deep
underground.
When piping is installed into waters, building should be located sufficiently close to shoreline,
preferably less than 50 m away. Waters should also be sufficiently deep, over 2 m right from
shore.