Solar Thermal Installation in Student Hall of Residence

By project ENERSELVES

Published on 03 July 2018

Spain

Extremadura

About this good practice

The initial situation was an existing system of SHW by accumulation, with a 4.000 litres tank and a natural gas boiler of 160.000 Kcal/h, ROCA model CPA-160. The solar installation will be connected to the existing boiler, the latter acting as a support system.
There are 150 people living in the residence, the consumption is steady in autumn, winter and spring, but nearly null during the summer. According to our building specifications, the climate zone and the support system, the consumption needed of SHW is 55 litres per day per person at 60ºC. This means the daily consumption needed is 8.250 litres when the occupation is 100%. The solar panels installed cover 54% of the annual consumption, which is a significant amount in this type of buildings.
The panels are placed on the roof of the residence, and they take up a total area of 124,32 sqm.
The installation is monitored remotely. The electric and control systems guarantee a proper functioning of the installation, obtaining a good use of the solar energy captured and ensuring a correct use of the auxiliary energy. In addition to this, it will ensure that temperatures don't exceed the maximum allowed by the materials, and the fluid will not reach the minimum permitted. The control unit has a multifunctional screen that allows the user to visualize the temperature of the collectors and the one of the accumulator.

Resources needed

The total budget required for this project was 78.738 €. From this amount, 30% came from a non-refundable subsidy.

Evidence of success

The annual production of renewable energy after the installation of the solar panels on the building is 77.238 kWh.
- The annual energy savings are 85.734,2 kWh.
- The economic savings are: 4.286,7 € per year.
Considering annual maintenance costs of 500 €, the payback period would be 14,5 years.

Potential for learning or transfer

The project is easily replicable in many other buildings throughout the region, due to the solar conditions we have. And specially interesting are public (or private) buildings like this one, with large roof areas. The payback period is the least attractive figure for private companies, but maybe some kind of public funding or special conditions for loans would tackle this hurdle.