Residential solar cooling and heating, Derio, Spain

Description of the application

Solar cooling and heating system with absorption chiller in a residential building in Derio, Bizkaia. 200 m of conditioned area are cooled and heated with a radiant floor system. The chiller allows heat pump operation during the heating season. During summer operation, heat rejection is done via the large rain water storage for irrigation.

General description of the system

The system technology for cooling is an absorption closed cycle with lithium-chloride solution. Heat is provided by a solar thermal system of heat pipe vacuum tubes panels (and an auxiliary system of oil when needed for heating and DHW) that is used for DHW, heating and cooling. The chilling capacity of the system is 10 kW with 50 kWh internal energy storage capacity, with a nominal driving heat temperature of 70-75 C. The heat rejection system consists of a large storage of 30 m volume with natural water exchange through use for irrigation and refilled with rain water. No wet cooling tower. During summer (mainly in June, July and August) the system runs in cooling mode and in heat demand mode in winter (December, January, February and March). Hot water is required all year round.

Central air-conditioning unit


closed cycle

Nominal capacity

10 kWcold

Type of closed system


Brand of chiller unit


Chilled water application

Radiant floor



Heat rejection system

Irrigation storage tank

Solar thermal

Collector type

Vacuum tube (heat pipe)

Brand of collector

Wolss Sunrain

Collector area

21.6 m2 aperture

Tilt angle, orientation

45 south

Collector fluid


Typical operation temperature

75 C driving temperature for chiller operation


Heat storage

0.6 m3 water

Cold storage


Auxiliary heating support


Use of auxiliary heating system

space heating in winter, space cooling and hot water

Auxiliary chiller


System performance

The monitoring data collected has not been jet analyzed or evaluated.

System reliability and overall success of the installation

Although quantitative data are missing for reliability analysis, the owner of the system is satisfied with the performance.

General information

Type of building  Residential
Location  Derio, Spain
In operation since  2007
System operated by  Lansolar
Air-conditioned area  200 m2
Chilling capacity  10 kW



Caption 1

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Specific information

Further specific information about the system are included in the filled in technical questionnaire.



For more information on the project please feel free to contact:

Olatz Ajuria