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2.4.12 Internal Heat Gains
Other notes: Ecotect does not provide calculation results for thermal lag. Therefore, an external software program has been used which defined the needed building element properties for the retrofit of building materials.
2.4.12 Internal Heat Gains
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Internal heat gains contribute to 60% of total heat gains in our base case model and it is
one of the most difficult to reduce as it has heat gains from people and equipment. It is
not really possible to reduce heat gains from people, the building is built for people and
they are going to emit heat, even though in reality they are likely to be significantly lower
as in the model exhibition centre was considered to be densely occupied throughout a
day as well as number of people is likely to often be lower in the library and office. Heat
gains from equipment can be minimized by choosing more efficient appliances, using
lighting smartly and exploiting daylight and promoting smart use of energy. In the pie
chart in Figure 35 base case internal heat gains by type can be seen. We can see that
around a third of gains come from people and that part cannot be reduced. However, all
equipment except lighting is contributing to around a half of internal heat gains and that
can be sector where most results could be achieved. Lighting heat gains are tackled in
another section, while possible reduction in other equipment heat gains is considered
here.
For our initial model typical values for equipment heat gains in offices were used from
CIBSE Guide A, 2006. However, they represent typical values and we can aim for more.
Moreover, computers are significant contributors to heat gains in offices and efficiency of
computers has improved a lot since the guide has been written 7 years ago. E.g. heat
gains for computers suggested by the CIBSE Guide are 155 Watts for 20 inch screen
computer, while current models of 21 inch screen computer have nameplate power
consumption of 100 Watts or if laptops are used power consumption can be even two
times lower.
