The European Commission aims to analyse the competitiveness of the European heating and cooling industry. Four case studies of successful and competitive deployment of heating and cooling solutions at a city level from selected organizations support this analysis. The case studies aim to illustrate how competitive renewable energy technologies such as solar-thermal, biomass, biogas and heat pump are in the context of different local factors across Europe, and what are their impacts on local communities.
The current case study is based on the desk search, field visit and interviews. It presents a renovation project involving 96 small houses in the Presikhaaf district of Arnhem (the Netherlands). As part of the renovation, the houses were fully insulated to lower energy consumptions; in addition, solar photovoltaic (PV) panels were installed on the rooftops (35 panels per house, 300Wp per panel) to generate electricity and heat pumps (air-to-water, 8kW) were deployed for space heating and domestic hot water.
This case study focuses on a renovation project involving 96 small houses (12 blocks, 8 houses per block) originally built in the fifties, in the Presikhaaf district of Arnhem, one of the largest city in the Eastern part of the Netherlands. The houses currently host about 400 people (on average 4.2 households per building). They are owned by a social housing company and have been recently refurbished and transformed in zero-energy buildings; in other words, the total amount of energy used by each house on a yearly basis is equivalent to the amount of renewable energy generated on-site.
As part of the renovation, the houses were fully insulated to lower energy consumptions. In addition, solar photovoltaic (PV) panels were installed on the rooftops to generate electricity and heat pumps were deployed for space heating and domestic hot water. More specifically, each house was equipped with so-called ‘energy modules’, i.e. small cabins placed near the front door and including all the devices required to meet the energy needs of the building (space heating, ventilation, hot water and electricity).
Key technical characteristics
- Expected lifetime 20 years
- Investment costs €10,000 to 12,000€ (energy module)
- Type of heat pump Air-to-water, 8kW (max)
- Coefficient of performance >3
- Yearly energy output (per heat pump) 12.8 MWh
- Space heating Wall radiators, hydronic distribution system, 40°C
- Domestic hot water (per house) 185-litre storage system, 53°C to 58°C
Two renewable energy technologies have been adopted to transform the 96 small houses in zero-energy buildings:
- solar PV for electricity generation; and
- medium-sized air-to-water heat pumps for space heating (with hydronic distribution) and domestic hot water (with a 185-litre storage system).
On average, a house similar to those renovated in Arnhem Presikhaaf consumed around 1,500m3 of natural gas per year (1,800m3 for corner houses) for heating purposes, which are equivalent to 2,800Kg of CO2 (3,380Kg for corner houses).
Considering that the 96 renovated houses are grouped in 12 blocks comprising 8 houses (of which 2 corner houses), the overall CO2 emissions for heating purposes before renovation were equal to about 283,000Kg. As zero-energy houses generate no CO2 emission, the combination of solar PV and air-to-water heat pumps allow saving no less than 283,000 Kg of CO2. Savings are certainly larger than this figure if one considers that, besides stopping using natural gas, households also stopped using conventional grid electricity.
- CO2 savings (total) 283,000 Kg
- Employment (net impact) No impact
- Social Improved living conditions for 400 low-income households