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The principle of the GHE

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.

1. Suction station for the ambient air
2. horizontal air distributing duct
the bed, leading the air to the bottom of GHE
accumulating bed (made of gravel)
air collecting bed
6. horizontal collecting duct - air intake for the house
humus-soil, lawn
foamed polystyrene
sprinkling installation

Basic properties and figures:
  1. 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.
  2. 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.
  3. 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. 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.
  5. 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.
  6. 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 137,000 m3/h.
  7. 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!!!
  8. 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.
  9. 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, or higher.
  10. 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.
  11. Using recirculation or a recuperator makes it possible to get 20÷30% of heat additionally.
  12. 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 in winter.
  13. 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.
  14. Air humidity after a GHE falls in summer (e.g. from 15.2g/kg to 12.7g/kg) and rises in winter.
  15. 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.

Filtering: of 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 air.
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 200€ (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.

Last change 20.03.2011
CHEAP AIRCON dition and heating ©

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