Solar Cooling: Proving the Paradox

The thermal comfort we enjoy in buildings, where we spend most of our days and nights, comes usually with very high environmental costs. Space heating, cooling and water heating constitutes for 47% of the energy consumption in buildings, according to DOE’s Building Energy Data Book 2008. The problem is that the electricity consumed comes from burning fossil fuels, a process that produces the environmentally unfriendly CO2 gas.

Simply asking consumers to cut down on their comfort is not a realistic solution to avoid the implications of climate change. No matter how much environmental awareness is being created, the majority of consumers will not change their standard of living simply for that reason. Instead, the main reason that consumers would change would be convenience and comfort.

The burden then falls on the industry to find realistic and innovative solutions. These feasible solutions must cut CO2 emissions without sacrificing comfort. This partly requires thinking in a fresh way by breaking away from conventional energy sources and starting to look into new renewable energy sources, breaking paradigms and proving paradoxes. This article is about how the sun can be used both to heat and cool our buildings and how that paradox is being proven as we speak.

Figure 1: Total U.S. Building Energy Use.

Myth:  Alternative sources cannot provide all the energy we need.

Reality: There is more free solar energy available than we could ever need.

The sun is the largest source of energy available to us today. Within 45 seconds, the Earth’s surface receives enough solar energy to fully meet the world’s entire energy needs for that day according to the DESERTEC Foundation.  This is the most abundant energy source available to achieve independence from fossil fuels.

Solar technology is very promising, but energy storage during night time and bad weather conditions still remains a technical problem faced by many systems today.

The current paradigm considers the sun as only a source for heating and electricity. Four major categories of solar technologies currently exist that harness the sun’s potential in order to provide heating solutions in the case of solar thermal technology and electricity in the case of photovoltaic (PV), concentrated solar power (CSP)  and solar chimney tower technologies.

Myth: The sun can only be harnessed for heating or electricity

Reality: Introducing Solar Cooling

Moving forward, we have to use the sun in new innovative ways and that is where Solar Cooling comes into play. Solar Cooling uses solar thermal technology to capture solar energy and then creates cooling without using electricity.

The sun’s radiation is more effectively used for cooling. The sun provides the most energy for heating during summer; however the demand for heating is very low during the hot summer period. The time of year when cooling is needed is when the sun offers the most energy. Therefore the potential to use the sun’s radiation for cooling will make use of a lot of energy which otherwise goes unused.

Solar Cooling offers substantial environmental, financial and social benefits over the conventional compressor driven cooling systems. Disadvantages with compressor driven systems are that they consume a lot of electricity and use refrigerants which damage the ozone layer of the atmosphere. Due to high electricity prices and high cooling demand in certain countries their use also becomes a high cost. Extended use of energy-guzzling systems during peak hours can also lead to electrical grid overload and black outs.

However, an innovative combination between heating, hot water and cooling technologies is the ideal solution. Using the sun’s energy for heating during winter and cooling during summer fully uses its potential all year round.

Figure 2: Single Family Home in Europe – Annual Energy Demand

Myth:  A technology providing renewable heating and cooling is still a thing of the future.

Reality:  Solar Cooling is a proven paradox.

Solar Cooling installations in operation successfully provide energy reductions and a minimum carbon footprint, without sacrificing comfort. Systems in operation today provide space heating, pool heating, cooling and domestic hot water (DHW) for high end villas, condos, blocks of flats, hotels, office buildings and hospitals around the world. The buildings are serviced with comfortable cooling during the summer, heating in the winter and plenty of DHW by day and night.

A typical Solar Cooling system is composed of solar thermal collectors, a ClimateWell SolarChiller, a heat sink and a distribution system. Solar thermal collectors capture the free solar radiation. The ClimateWell SolarChiller transforms the heat into cooling during summer without using electricity or refrigerants. The free solar radiation, which is not transformed into cooling, is used to warm up DHW and pool water where applicable. The pool acts as a heat sink used for heat rejection. Cooling towers, air-cooled condensers and geothermal boreholes can also be used for heat rejection. The indoor cooling and heating comfort is finally distributed throughout the building by a build-in radiant floor distribution systems, fan-coils or air ducts. The unique storage capability of this particular system allows it to service the building with comfort even during night time and bad weather conditions.

An investment in this system saves energy and generates financial savings over time. The energy savings generate CO2 reductions. Grid overload and black outs are also less likely during peak hours.

The proven technology paradox harnesses the most abounded source of energy, breaks away from polluting conventional energy sources and shows that comfort can be achieved without high costs.

Figure 3: Solar Cooling 3-in-1 Solution, Credit: ClimateWell.

Dan Radu is part of the Sales & Marketing team at ClimateWell in Stockholm. He was born in Romania, studied in Canada, worked in Russia, Canada and now in Sweden. Before ClimateWell, Dan Radu worked at Fortune 500, Small Medium Enterprise and Non-Profit organizations. ClimateWell sells Solar Cooling solutions. Its technology stores energy from a solar panel in a battery using salt, which can then be used to generate either cooling or heating.