Headquarter building of CARTIF in Valladolid, Spain

Description of the application

The solar installation is located in CARTIF Foundation Building 1, Boecillo, Valladolid, in the middle of Spain (Lat. 41 32, Long 4 45).
The weather of exposure is an extreme continental type, which characterises by its cold winters and warm summers and by the high temperature oscillations between day and night.
The building has a glass-front that foster heat gains by radiation mainly in those zones facing south.

General description of the system

Working hours in the building go from 7:00 to 15:00. This leads to a higher energy demand in the morning than in the evening. It must be taken into account that this regime penalizes this cooling application because when maximum temperatures are reached in the tanks, and best performances can be obtained, there is no cooling demand. This is precisely the reason that makes design be carried out with a high ratio of accumulation (50-75 l/m). All the energy available that has not been used will be accumulated throughout all the afternoon to be used during the morning of the following day.
Regarding internal gains, it has been considered that there are 8 people seated typing (light working), with their own computers (400 W) and two copiers (2.5 kW). Artificial lighting is made with low consumption lamps (20 W/m). The calculated daily energy consumption for each month is 199 kWh/day in June, 209 kWh/day in July, 199 kWh/day in August, and 169 kWh/day in September.
Thanks to an estimation of the hourly refrigeration loads, it can be seen that the highest cooling demand is 29 kW and takes place in August. The chosen machine has been a Yazaki WFC 10 (35 kW).
The solar system installed is an absorption one, working with two different solar fields.

Central air-conditioning unit


closed cycle

Nominal capacity

35.2 kWcold

Type of closed system


Brand of chiller unit


Chilled water application

fan coils



Heat rejection system

wet closed cooling system

Solar thermal

Collector type


Brand of collector


Collector area

37.1 m2 aperture

Tilt angle, orientation

40, 0 west

Collector fluid


Typical operation temperature


Collector type

evacuated tube

Brand of collector


Collector area

41.2 m2 aperture

Tilt angle, orientation

40, tracking

Collector fluid


Typical operation temperature



Heat storage

8 m3 water

Cold storage

1 m water

Auxiliary heating support

235 kW gas boiler

Use of auxiliary heating system

space heating, cooling and domestic hot water

Auxiliary chiller


System performance

During summer 2007, the following data was obtained:
Average solar fraction of 25%, with tips to 40%.
About the solar collectors, a 35% efficiency average was obtained, with maximum power of 35 kW.
Thanks to storage, in operation was obtained a power of 60 kW in generator, all given by the solar installation.
The energy produced in a medium day is of 2.45 kWh/m, with a incident energy of 7.08 kWh/m as an average during the whole summer.

System reliability and overall success of the installation

Having a high level instrumentation tools allowed a continued modification of the installation, what led to a better production and use of the solar energy.
Some installation faults were detected, and were corrected: faults in the insulation, valves badly installed, etc
Experience was gained about integration between solar cooling installations and conventional installations, detecting which practises are recommended, which are not, in the design part, but also during the exploitation of the installation.
Another good idea was to have a flexible distributed control system that allows the implementation of specific control strategies.
Were implanted, among other things:
- Start of the solar installation by critical radiation
- Control of match flow in the part of solar generation
- Control of the condensation temperature depending on the generator temperature
The results were satisfactory, obtaining an important improvement for the results of the installation.

General information

Type of building  commercial
Location  Boecillo, Valladolid, Spain
In operation since  summer 2000
System operated by  the owner
Air-conditioned area  200 m2
Capacity  35.2 kW


Plant of the building
Caption 1
Building view
Plant of the building
Building view

Clicking an image opens the gallery view.

Specific information

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


1.2 M


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

Marie Proville