Oilon ESi 6-17, Installation And Operation Manual

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increases by a few degrees. The brine is then pumped into a heat exchanger inside the
heat pump: the
evaporator
. In the evaporator, thermal energy is transferred from the
brine to low-pressure refrigerant, evaporating the refrigerant.
In vertical systems, a deep well is bored into the bedrock. In horizontal systems, an extensive coil of
plastic pipe (PEM 40/10) is buried to a depth of 1–1.2 meters or more or submerged in a body of water
(minimum depth: 3 meters).
The brine solution includes ethanol to prevent it from freezing. After being pumped through the brine
circuit, the temperature in the brine to the evaporator is approximately 0 ºC, but can be higher in the
summer and lower in the winter.
The compressor unit
From the evaporator, the refrigerant vapor is transferred into the
compressor
which
compresses the vapor to a high pressure. At this stage of the process, the refrigerant’s
temperature increases to over 100 ºC. After the compressor, the refrigerant is referred
to as
hot gas
.
Hot gas is transferred from the compressor to heat exchangers ( desuperheater and
condenser
). Heating water from the
storage tank
circulates through these heat
exchangers, taking thermal energy from the hot gas. As the refrigerant releases its
thermal energy, the water heats up, and the refrigerant cools down, condensing into a
liquid.
The liquid refrigerant is transferred through a filter drier into the expansion valve ,
where the pressure of the liquid refrigerant decreases. The refrigerant is transferred
into the evaporator, and the cycle starts over from the beginning.
Desuperheater
As heat is extracted from the hot gas, its temperature decreases to a point where the
refrigerant starts to condense into liquid. This point is close to the temperature required
for space heating (typically around 35–55 ºC). However, after the compressor, the
temperature in the hot gas is approximately 120 ºC, which means that it must first cool
down. Instead of letting the heat dissipate, it can be extracted with a desuperheater .
The extracted superheat can then be used to bring pre-heated domestic hot water to
its final temperature.
Note that EMi 22P and EMi 43P models have no desuperheater; instead, all thermal
energy is transferred to the heating water via the condenser.
Storage tanks, heating circuits, and domestic hot water
It is possible to connect multiple storage tanks for storing the thermal
energy produced by the heat pump. These storage tanks vary in size
and construction.
Cool water from the bottom of the storage tank circulates through the compressor
unit which heats up the water. Once heated, the water returns to the tank at a higher
level. The water in the hot water storage tank circulates through the building’s heating
system, which consists of one or more heating circuits.
M8010 2204EN 7 (75)