CONCENTRATING SOLAR THERMAL COLLECTORS FOR COOLING …kgh-kongres.rs/images/2016/doc/ppt/49-Drosou.pdf · Vassiliki DROSOU, Elli KYRIAKI, Argiro DIMOUDI, Agis M. PAPADOPOULOS 47

CONCENTRATING SOLAR THERMAL COLLECTORS FOR COOLING OF BUILDINGS:

AN ASSESSMENT FOR GREECE

Vassiliki DROSOU, Elli KYRIAKI, Argiro DIMOUDI, Agis M. PAPADOPOULOS

47. Međunarodni kongres i izložba o KGH, Beograd, 30.11–2.12.201647th International HVAC&R Congress and Exhibition, Belgrade, Nov.30–Dec.2 2016


CST use a combination of mirrors or lenses to concentratedirect beam solar irradiation to produce heat, electricity orfuels.

CST use only direct sunlight (DNI, Direct NormalIrradiance), i.e. the fraction of solar radiation that isnot reflected by clouds, fumes and dust in theatmosphere and reaches the Earth's surface as aparallel beam.

CST reach medium (100 – 4000C) and high level temperatures (> 4000C), depending on the technology used and the application needs.

Concentrated solar thermal (CST) systems principles


Concentrated solar thermal (CST) technologies

Solar cooling technology is based on the use of solar thermal energy for producing cold water in the appropriate temperature level for space cooling purposes.

The cooling needs of a building coincide with high solar radiation.

The main advantages of solar cooling systems are: - the avoidance of using conventional resources, - the use of environmentally friendly working fluids,- their ability to be installed as stand-alone systems or in combination with

conventional cooling systems, - their contribution to electricity consumption stability of a country / energy

security / reduction of conventional sources consumption / CO2 emissions.

Commercial solar cooling systems can be classified into "closed systems" which have solar chillers providing cold water for the air conditioning of a building and "open systems" (air), based on the technology of evaporative cooling and dehumidification (DEC: Desiccant Evaporative Cooling).


Solar cooling principles

A typical solar cooling system consists of the solar field, the ab- or adsorption chiller, the thermal storage, the secondary hydraulic equipment (cooling tower, pumps, heat exchangers, piping, valves) and the control system.


Schematic diagram of a "closed" solar cooling system

Α typical residential building which consists of three floors and a basement, built in 1997, with a total heated area of 400m2.


Building envelope’s energy performance characteristics


Energy performance characteristics

• 35 typical residential buildings

Solar Village 3, Athens, Greece, 1990


Buildings’ cooling needs, with respect to location

368 CDD 24oC

255 CDD 24oC

415 CDD 24oC


CST collector technical characteristics


CST solar field technical characteristics


Solar chiller technical characteristics“Broad” two-stage steam solar chiller, model BYS100,Nominal cooling capacity 1.163kW.


Simulation resultsCooling capacity versus DNI

Thessaloniki Athens Heraklion


Simulation resultsThermal energy output versus cooling energy

Thessaloniki Athens Heraklion


Simulation results& comparison of simulated and published results

Case A: simulation studyCase B: published results, SAC with flat plate


• Solar cooling can become a promising solution for the clean, energy thrifty and sustainable air-conditioning of urban buildings

• CST collectors use can yield significantly higher useful thermal output than flat plate collectors

• CST allow the use of two-stage sorption systems that operates with a significantly higher COP than the single stage.

• CST systems can be beneficial, when it come to utilizing a given, limited, available area of installation (eg the building’s flat roof) for low and medium temperatures.

• CST systems have to be part of an integrated whole solar approach, covering space heating and cooling and also hot water production.

Conclusions


Documents

CONCENTRATING SOLAR THERMAL COLLECTORS FOR COOLING …kgh-kongres.rs/images/2016/doc/ppt/49-Drosou.pdf · Vassiliki DROSOU, Elli KYRIAKI, Argiro DIMOUDI, Agis M. PAPADOPOULOS 47