Solar Thermal's Untapped Heating Potential, Part I

Apricus is a global company that provides simple and effective solar hot water solutions. Apricus' solar thermal systems are used in both residential and commercial applications, helping families and businesses battle the effects of climate change and rising energy costs. I recently had the opportunity to parley with Mick Humphreys, Founder & CEO of Apricus.

Solar thermal is deemed to have far higher efficiency than solar PV, and more and more homeowners are catching on to this fact. Questions about the technology abound. For instance, a lot of people don't know that solar power can be used to heat space as well as water. In Part I of this interview, Mick expounds on several applications for solar thermal.

Most homeowners associate solar thermal with water heating. Tell me more about its space-heating applications.

"Space heating can be a major portion of a household's energy cost, particularly in really cold regions such as NE USA and up into Canada.  With the high price of heating oil and other energy sources, it is becoming increasingly important to look at how to supplement regular dirty energy with renewables.  Solar thermal is a perfect choice because the conversion efficiency is very high, and can work effectively, even in freezing conditions because of Apricus' innovative evacuated tube design.

"One type of space heating application that uses solar thermal is forced air heating.  Once solar radiation heats your home's water – which can be used for everything from showers and sinks to spas and hot tubs – a coil is placed in your home's return air duct.  As air passes over it, the warmth of the coil heats the air, greatly reducing the need for heating by other energy sources and reducing your bills significantly.

"Of course it is not as sunny in the cooler months when space heating is important, but there is still a lot of energy that can be harnessed and contribute significantly to reducing energy costs.  The evacuated design of the Apricus solar collector provides excellent insulation from outside temperatures – so heat production is efficient even when it is cold outside.

"To significantly reduce a home's environmental impact and reduce energy bills, a homeowner could install, for example, 3 or 4 Apricus solar panels to provide virtually all of a household's hot water year round and 20-50% of space heating; depending on the size of the house, house insulation properties and climate.  

"Ultimately solar thermal collectors produce heat that can be used to supplement the boiler for any form of space heating: be that forced air, radiant underfloor systems or traditional radiators." 

How can solar thermal be used to heat floors?

"In a radiant heating system that is installed in a home's floor, heating costs for a home can be reduced significantly while providing the added benefit of a heated surface to walk on during cold winter nights.   

"For radiant floor heating, underfloor piping is required and this is generally installed when the house is being built, although many retrofitting options are becoming available as the application gains in prominence.  These plastic pipes are installed in a serpentine fashion underneath the floor boards, and their heat is transferred into the flooring and radiates up, warming the entire house as the hot air rises. This application can offer not only a new level of comfort with warmed floors to walk upon, but also helps to reduce overall heating costs for a home."

What are the top 4 solar thermal applications that you recommend to homeowners and why?

1. Hot Water – By far and away, the most immediate benefit of a solar thermal system is for all our daily water uses – showers, washing dishes, and household sinks.  On average, a house of 4 people uses about 15kWh of electricity each day or 51,180 BTUs of gas heating to provide the energy needed.   
2. Spa/Hot Tub Heating - This is also a fantastic use of solar as you just need to maintain the temperature and one solar panel can do this effectively.  The system can be integrated into the hot water system, so when the spa/hot tub is not being used that heat is still contributing to hot water requirements.
3. Space Heating – As is mentioned above, there are a number of space heating applications that solar thermal provides very effectively.  Forced air heating, radiant underfloor heating and radiator applications are all cost-effective ways to put a solar thermal system to great use.
4. Pool Heating – Another application of solar thermal heating is pools.  Different from spa and tub heating above – which require a smaller amount of water to be heated to a very high temperature – pool heating requires that a large body of water be heated by a couple of degrees.  Solar thermal systems can help create a comfortable temperature in your home's in-ground or above-ground pool.

-Thanks Mick! Part 2 of this interview will revolve around the bigger picture surrounding solar thermal applications, including costs, challenges, and a comparison with solar PV.