The principle of the Ground
Heat Exchangers (GHE)
Warms up in winter, cools down in summer
and cleans the air the whole year long.
In our climatic
zone the temperature of soil at the depth of 1÷4m remains steady at the
level of 100C or 500F (+/-1.50C) or
(+/- 2.70F) throughout the year. To make use of this energy,
the Ground Heat Exchangers (GHE) have been invented. At least a dozen or
so GHEs, operating in Poland, confirm that the outside air, flowing
through a bed, located at this depth, warms up in the coldest winter of
200C or 680F, and cools down in summer from 300C
or 860F to 200C or 680F.
The construction of the GHE is
designed as a natural bed of clean, rinsed gravel, located in soil. The
air, flowing through the gravel, is, depending on the season of year,
cooled down, warmed up, dried, or humidified, and (always) filtered. The
direct contact with the surrounding subsoil facilitates rapid
regeneration of the gravel bed.
- Thanks to its simple construction,
and possibility to build of readily accesible and chep materials,
the GHE can be made in almost any place and under any conditions.
This is why it can be widely used for ventilating, air conditioning
and thermo-ventilating purposes.
- A cheap way of using the natural
energy from a little depth of the ground to cool down and warm up a
stream of ventilating air.
- Utilization of the Ground Heat
Exchanger can surely be interpreted as exploitation of renewable
energy. Any investor, who decides to build the GHE may apply for a
subvention or preferential investment loan from the European
Community or the National Fund for Environment Protection („Narodowy
Fundusz Ochrony Srodowiska”), with its regional branches at the
offices of regional administration („Urzad Wojewódzki”).
- 4. By using GHE, additional savings
of the costs of the air conditioning installation automation can be
made. This is because of the GHE inertia, as the properties of the
outgoing air, are highly independent of any changes in the ambient
air at the exchanger inlet - its parameters are stable for a long
time and they do not have to be regulated currently.
- The parameters of the air leaving
the bed, change very slowly, the changes being noticeable only at
few month intervals. These changes are practically not detected
within a single month. This is an advantage, because all picks of
ambient temperature, are reduced, both daily changes as well as any
abrupt cooling or heating within the following days.
- In summer, thanks to a high output
and low operating costs of the GHE, only ambient air can be used for
ventilation, with no need of mixing it with used air (recirculation).
The total output of the biggest GHE operating in Poland reaches
- You only pay the costs of
transmitting the air through the bed (resistance of ca. 100 Pa) and
not the costs of cooling or heating the air!!!
- The GHE satisfies the whole demand
for cool in summer. The proportion of energy intake (a fan) to
energy output reaches 1:30÷35 in the hottest summer days.
- The advantage of the GHE air stream
supplying recuperators is that a cross-flow heat exchanger does not
freeze even at minus 200C or 680F, the
temperature at the inlet being around 00C or 320F,
- In the coldest winter a GHE can
secure up to 50% of ventilating heat. Then the proportion between
the energy intake (a fan) and output reaches its maximum of 1:35÷45.
- Using recirculation or a recuperator
makes it possible to get 20÷30% of heat additionally.
- The maximum air temperature
gradients before and after a GHE are the following: 10÷120C
or 500F÷ 53.60F in summer, and 18÷200C
or 64.40F÷680F in winter, this data being
valid for max. and min. ambient temperatures of 320C or
89.60F and -200C or -40F
respectively. The average thermal effect of the bed reaches 1KW/m3
- The best energetic effects can be
obtained during the extremal periods, i.e. at a low ambient
temperature in winter and high temperatures in summer. Thus all
tiresome temperature picks are levelled.
- Air humidity after a GHE falls in
summer (e.g. from 15.2g/kg to 12.7g/kg) and rises in winter.
- Service-free operation and no
maintenance. It has been proven by the 23 years old pilot
installation at Polanica Zdrój (volumetric output of 500m3/h)
and 20 years old EXBUD-SKANSKA installation in Kielce.
biological impurities - fungi, alergenes, bacteria - is another
advantage of the GHE. Following 15 years of the gravel bed exploitation,
the Section of Epidemiology of „Sanepid” (sanitary and epidemiology
services) rendered the following expertise: „As a result of a series of
investigations it has been concluded, that the air at the outlet of a
heat exchanger contains several times less microbes and alergenes,
compared with the air at the GHE inlet.”
Where the exchangers can be used? Detached houses, shops,
restaurants, warehousesblocks, factories, schools, etc. Unlike
traditional air condition, which is usually , office installed only in
representative rooms, GHE, because of its low investment and operating
costs, can be used to supply the whole buildings with the conditioned
The costs of designing and installation are lower, if not much lower
than in case of the traditional air condition. Installation of a GHE for
a detached house requires an area of at least 8÷12m2. Once
the installation is completed, grass or other plants can be sown/planted
in the area. Approximate cost of installation reaches +/-5000 PLN (1500
€) (concerns preparing GHE by oneself, using hired equipment, i.e.
excavator and transport). Our company offers guidelines for
self-constructing a typical exchanger. This documentation (in Polish)
for a detached house of a usable floor area of 200m2 costs
100€ (plus postage). The documentation is so complete and clear that
almost anybody can prepare their GHE step by step. And it surely will
cause no problem for any Constructing Manager. Please, call us, and you
will be invited to the nearest GHE to see it working.
our address and fax number:
ul. Graniczna 49j
PL 41-408 Mysłowice
Tel +48 32 2016168
If you don't speak Polish, pls. contact us through fax or e-mail. We are
sorry, but our English speaking person is not always at the office.