Nowadays efficiency measures are more and more important because the price of the energy is
increasing every year. Moreover, saving energy it is also important for decrease the
environmental impact.
Kastvallen is a hockey arena built in 1997 that cools the hockey rink with electric compressors.
The changing rooms are heating by using district heating. Actually the total invoice of
electricity is above the 800000 SEK. Meanwhile the district heating invoice reaches the
60000SEK. The aim of this project is reducing the amount of the electricity and heat invoice
promoting smart energy improvements.
The improvements proposals can be divided in three sections; energy savings of the changing
rooms, efficiency increase of the compressors and dehumidifier energy savings.
For heat the tap water and the changing room’s ventilation it is suggested to take profit from the
heat released at the condenser and so reduce its heat load requirements. For this proposal two
different configurations are studied.
In order to increase the efficiency of the compressors the possibility of reducing the condenser
temperature will be studied. Three proposals will be studied to carry out this commitment;
Installing a condensing temperature control, installing a evaporate cooler and having a snow
storage.
Finally, one of the largest consumers of electricity in Kastvallen ice hockey rink is the
dehumidifier. The current dehumidifier works with a desiccant wheel. The desiccant material
extract the moisture from the processed air flow, after that the desiccant has to be reactivated
with ‘fresh air’. This reactivation air needs to be heated 95ºC, so the waste air released after the
reactivation of the desiccant is air at high temperature.
The first proposal is preheat the reactivation air with the hot waste air in order to reduce the
heating requirements. The second step is studied the possibility of heating the air with district
heating, taking into account that district heating is three times cheaper than electricity. The last
proposal is to combine preheating and heating with district heating.
All the previous energy improvements proposals are studied with empirical and analytical
methods and using the knowledge gained during the previous years of studies. The study concludes that the best proposal for the dehumidifier is combine the preheating and
heating with district heating. For the refrigeration cycle, the study concludes that installing a
controlled temperature control is the best option if the price of that is lower than 334726 SEK. If
not the best option is heating the rooms and the ventilation with the condenser of the
refrigeration cycle. These measures could reduce between 8% and 20% of the total energy
invoice. Evaporative cooling and snow storage would be studying after with the data of the first
year of the condensing temperature control; if it is installed.
