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Title:
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Monitoring KODI : energieheipalen als fundament onder een energiezuinig gebouw
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Author(s):
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Published by:
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Publication date:
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ECN
Energy in the Built Environment
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1-7-2002
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ECN report number:
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Document type:
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ECN-C--02-035
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ECN publication
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Number of pages:
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Full text:
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45
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Download PDF
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Abstract:
The Kodi building in Heerhugowaard has been equipped with an energy-efftcientheating and cooling system, in which heat and cold are extracted from
the soil underneath the building using 'energy-piles' (foundation piles
with integrated heat exchangers). Relevant data, such as heat flows,
electrical power of heat pumps and circulation pumps and temperatures
have been collected from April 2000 to April 2001, and were analysed
to assess the performance of the heating and cooling system. The main
conclusions are:
- The subsoil system has been functioning very well, in spite of the
fact that the amount of heat extracted in wintertime appeared to be
a factor of 10 higher than that injected in smnmertime. The imbalance
could in theory result in 'thermal exhaustion' of the soil, but no such
phenomenon has been observed in the measuring period. The average power
of heat extracted in wintertime appeared to be 10 W/m (per m length
of pile).
- There has not been any danger of fieezing of the soil around the
piles, since the fluid entering the piles had at al1 times been warmer
than °C. The soil around the piles was a few degrees C warmer.
- The performance of the heat pump appeared to be somewhat lower than
expected, having a Carnot-efficiency of 35-40%. Year averaged values
of COP (Coeffient Of Performance) and SPF (Seasonal Performance Factor)
were 3.8 and 2.6 respectively.
- The PER (Primary Energy Ratio) of the heating and cooling system
as a whole has reached values of more than 100% during most of the measuring
period. Improvements are possible by reducing the amount of auxiliary
power.
- When using open distributors to couple two hydraulic circuits, the
flow rates in both circuits should be identical to avoid mixing of fluids
of different temperatures, leading to exergy losses. Mixing also results
in a higher than necessary temperature lift for the heat pump, resulting
in lower values of the COP.
- The second heat pump has been in operation for only 240 hours (85
equivalent full load hours) in the measuring period. From the point
of investments, a simple gas-fired boiler would have been a better choice
for peak heat demands.
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