Spanish researchers want to expand the use of solar collectors for heating and air-conditioning of large office buildings to reduce energy consumption.
The team from two Madrid-based universities is designing a system that would integrate solar collectors, a gas-based heat generator and an absorption refrigerator into one complex unit.
They believe such a device would enable reducing energy consumption and cutting down CO2 emissions.
"Current regulations state that the installation of solar panels in buildings is only compulsory in order to meet the demand for domestic hot water, but very few offices have either showers or kitchens,” said Pedro A Rodriguez, a professor at the University of Carlos III, who has led the research. “Consequently, the idea behind our proposal is that a part of the demand for heating in winter and for air-conditioning in summer could be met with solar power."
Despite some shopping centres already using complex generation systems capable of producing electricity, cool air and heat, the idea of integrating solar collectors into the scheme is entirely new.
In the conventional systems, gas engines generate electricity, with the residual heat being used for heating in winter. In summer, this heat powers an absorption refrigerator that provides air-conditioning.
The results of the study have been published in the recent issue of the Applied Thermal Engineering journal.
At this stage, the researchers admit, the main drawback of the innovative design is its high acquisition cost.
"The size of the investment necessary for the installation of a solar power plant means this hybrid solution takes longer – more than 14 years – to pay for itself,” said Carmen Rodriguez Hidalgo, a researcher from Madrid’s Technical University.
“However, the system allows greater reductions in CO2 emissions, ranging from 1,527 tonnes to 1,760 tonnes per year. It also produces primary energy savings and a slight increase in annual profits."
The prototype system was designed considering the average energy needs of buildings in the Madrid region, taking into account monthly climatological data such as temperature and insolation. It can be adjusted to the needs of each individual office, responding swiftly to weather changes.
The prototype system, suitable for a 50,000m2 business park, has the capacity to supply 1.7MW of electricity, 1.3MW of energy for heating, and an additional 2MW for air-conditioning.