In the municipality of Galapagar, an area of 36 km² with a population of 32,930 inhabitants, Madrid’s most sustainable Town Hall was built. The design and installation of a geothermal heat pump system provides high energy efficiency at a lower cost than conventional heating or cooling systems. The commercial area attached to the town hall building also benefits from the use of the renewable system.
- Company: Galapagar Town Hall
- Location: Galapagar, Community of Madrid, Spain
- Savings of 75% in heating and up to 50% in active and passive cooling
- CO2 emission savings of 50 tons/year
- 70% economic savings in terms of energy consumption
No more fossil fuels at Town Hall facilities
In 2013, it was decided to build a new Town Hall in Galapagar, as the increase in population in the town had led to an increase in staff in the Town Hall, which meant the old building did not have enough capacity. During the construction of the new building, the possibility of eliminating fossil fuels in the facilities was brought up. As a result, the construction of a thermal energy production plant by means of geothermal energy was proposed. The installation, done by CLYSEMA under an Energy Performance Contracting (EPC) scheme, is the largest geothermal installation in a town hall in Spain, together with the one of Amorebieta (Basque country) and the first in the Community of Madrid.
The installation has been praised by many, and in 2015 it was awarded the prize “the Best Geothermal Installation of the Community of Madrid” by the General Directorate of Industry, Energy and Mines.
Overcoming the challenges of building a sustainable Town Hall
One of the main barriers for this kind of projects is the high initial investment, specially for the public administration. At the time the Town Hall was built, the Spanish Public Administration was going through a period of low expenditure on “non-essentials”. Therefore, one of the novelties of this project lied in the collaboration between a private company (Energy Service Company – ESCO) and the public administration to undertake an environmental protection project. The private company executed the initial investment and operated the facility for 10 years. As the monthly expenditure to payback the ESCO is lower than the savings on the energy bill, the project is profitable for both parties.The total investment added up to EUR 400,000 with a payback period of 10 years.
Another challenge found in the execution of the project was the lack of space for drilling. As a result,in order to achieve the desired power, the low enthalpy geothermal collection had to be designed deeper than it has ever been done in Spain, achieving depths of 200 meter. This technological challenge was successfully overcome by CLYSEMA’s technicians. In geothermal projects such as this one, the process followed for implementation is:
- First, the desired power is estimated based on expected consumption
- Based on this, the length of the drills are calculated
- This, in turn, will result in a calculation which will establish the necessary number of wells
In Galapagar, the last two steps were reverted, as the technicians first calculated the number of needed wells and then estimated the depth needed to obtain the desired power.
When the Town Hall was built, it was decided to also construct an adjancent commercial area for local businesses. The heat pump installed has a power of 100 kW which means that when both the commercial area and the Town Hall are operational at the same time, on the days of greatest demand, 100 kW will not be enough. Consequently, the project included the design of an indoor aerothermal heat pump of 100kW of additional power for those days of greater demand. The aerothermal heat pump was placed in parallel following the scheme designed by the technical team in terms of optimization of consumption, giving priority to the most efficient systems all the time. The system can obtain at specific times a coefficient of performance (COP) higher than 8 and the plant produces 400,000 kWh/year.
Heat is distributed by radiant floor throughout the town hall and the building has five thermostats in five differentiated areas. These thermostats are read to regulate the temperature production, never in detriment of user comfort.
To manage energy consumption, a time control system was implemented for all areas of the building to adapt it to the use of the premises and to avoid waste such as the recirculation of the sanitary hot water, which results in unnecessary expense of both pumping and thermal losses very common in buildings.
At the head of energy efficiency
Glapagar Town Halls’s is an exploitation of a low-enthalpy geothermal resource, so no high-enthalpy, high-pressure geothermal fluids will be used at any time, nor will any water resources be extracted. In this way, a heat exchange takes place between the circulating antifreeze fluid and the ground. In winter, the ground transfers the heat it stores to the fluid and is used for heating, as the geothermal pump raises this temperature with its efficient compressor to more than 55°C if necessary. In summer, the fluid transfers the excess heat from the building to the ground so that cooling is obtained.
The energy and environmental advantages of using this technology are remarkable, since it takes advantage of a widely available renewable resource that also offers great energy efficiency and allows for proven savings of up to 75% in heating mode and 50% in active cooling. In passive cooling, where the circuit fluid cools the building without passing through the heat pump’s compressor, with electricity consumption due exclusively to the circulation pump, the savings are even greater. This significantly reduces CO2 emissions from the use of fossil fuels for air conditioning.
Thanks to the agreed EPC and the installation of the pumps the following savings are obtained:
- The annual energy cost for heating and cooling of the new town hall using traditional technologies would have been EUR 60,000/year and at present the cost is 54,000 euros considering that the amortization of the installation executed by CLYSEMA is also being paid.
- In addition, CO2 emission savings add up to 50 tons /year.
The Town of Galapagar is becoming a reference for its work on achieving energy efficiency through measures such as the installation of a biomass boiler in a local school, the implementation of LED lighting in almost 50% of public lighting, ant he installation of a geothermal system that allows the council savings of more than 70% in the energy field.
Text: Creara (Madrid) Content provider: Clysema