Monday, October 20, 2014

New Technology Renewable Energy System:

Wow!  I just had a 2 hr conversation with Bruce Gray.  It was at a presentation organized by Terrell Wong and Kathy Garneu, here in Toronto. Bruce is the inventor and founder of a disruptive technology called Sunpump, (see located in Vancouver. They have a new heating and cooling technology that blows everything else right out of the water.

It is a major shift to a new way of the using the very familiar vapour compression cycle. We're all familiar with the mini split heat pump. They have been around quite some time, and over the years, their efficiencies have improved. In the last month or so Mitsubishi released (in Canada) their FH09 mini split heat pump with a SEER rating of 30.5. That is news in itself! But tonight, I learned about something even better.

The Sunpump is a heat pump combined with a solar thermal panel - but there is no glycol, and no water. The thermal panel hosts refrigerant. In addition, there is no outdoor fan. The thermal panel sits on the roof or on the wall, and exchanges heat with the sun and the environment, without any moving parts on the outside of the building. The panel is a solid plate of aluminium with many small channels running through it. This configuration is classically difficult to produce - but the company has overcome this challenge with the employment of 3D printing, so the panel is not two sheets stamped and brazed or somehow fused together. It is a monolithic plate. It is anodized to be blackish, and has a hydrophobic coating on it. What is amazing about this whole concept is a number of things - and I feel dumb for not having thought of it - but the elegance of the whole configuration is just wonderful. Unlike regular evacuated tube or flat plate solar panel systems, there is no stagnation, no drain-back, no thick lines to the roof (the copper lines are 1/4" and 3/8" dia), no freezing, no glycol, no pump, no fan, no nothing. The system is very economical to purchase because there are so few moving parts. The only moving part is the compressor rotor and perhaps a valve. But efficiencies are huge! Studies show that installed COPs of mini splits are about 2.5 and groundsource heat pump systems, 3.5.  This new technology has a COP of about 7 or 8, in the installed condition, and I think these numbers are not exaggerated. If you are a little familiar with heat pumps and heat transfer, you'll see why. Even evacuated tube solar panels have working fluids (water, glycol) that struggle to take heat from an environment that is say -5 Celsius or colder outside.  But when you have direct exchange with the R410a refrigerant, which is operating at much lower temperatures, you can extract heat from much colder ambient conditions. In addition, because there is no fan, there is no bulk movement of air over the heat exchanger (in this case the panel - in a regular mini split outdoor unit, it is a finned heat exchanger). This means there is no freezing of moisture on the heat exchanger, and a significant portion of the heat exchange is carried out via radiation. To top it off, the company also offers these panels with PV cells grafted onto one side - so you can get electricity (just like a standard PV panel) as well as heat. There are numerous hybrid panels on the market, including PV with Air, PV with water/glycol - but this is PV with R410A refrigerant. This is a big step forward. And, finally, the system's output side seems available in more than one configuration (which was always something I hated about mini-splits - their lack of ability to have a hot water output at a good price). Sunpump offers their units with hot water outputs as well as straight refrigerant outputs - so their systems can work with hydronics as well as air-based HVAC systems. BTW, the system cools as well as heats.

Costing is only about $1/watt of total output - I believe this includes the panels, accessories, and heat pump. This means the system is cheaper than many many systems out there, and I think will even compete with the low price of natural gas in North America. Apparently they intend to compete on installation costs with electric baseboard heating!

The company is well developed already, has sold much product, and has CSA approvals on their products also. And the panels produce some 7 to 8 times as much energy as regular solar PV panels today produce (!!! - I know !). They also have partnered with a financing company so builders can have these panels for ZERO dollars down - the company recoups the money by having the consumer pay their energy bill savings towards the loan.

So, this is the biggest, baddest news out there in the world of energy systems. Absolutely must look into this for every project, not even just low energy buildings. Remember the panels work at all hours of the day, (the thermal aspect of them), and on all sides of the house - they are about twice as productive on the south side, but even on the north side, they perform well compared to other heat pump systems.

I discussed groundsource with Bruce as well.  He said their testing showed ground source loops to eventually degrade in their heat transfer capability due to freezing and shifting of the soils around the pipes - but the performance potential is ultimately limited by the working fluid. There have been what are called direct exchange systems in the past, in which refrigerant is passed directly into copper pipes in the ground - but the copper seemed to be unreliable and developed leaks, etc.  (I 've heard also of the difficulties in these systems). One great advantage of the groundsource system is that they tend to store the summer's heat in the ground, and then, later, store the winter's cold in the ground as well, reducing both heating loads and summer air conditioning loads. This system does not have an inherent storage aspect like the groundsource, but the simplicity and greatly increased efficiencies seem to me to make things much more worthwhile with these thermal panels - ultimately groundsource has some environmental issues and is really quite expensive, as well, and involves a fair bit of plumbing and pumping. The Sunpump system does away with that. Storage can be added to the system of course, with the use of a water/ice tank.

So - it is not often I am impressed with a new product - but this is one of those times. The concept is absolutely fantastic, and the product appears to have great potential.

Actually, I was badly conflicted in writing this article. They are currently in explosive growth mode, so production is very tight and it may be hard to get a unit right now - and of course, I want one, so I didn't really want to tell everyone about it - but hey - must do the right thing......and tell you all.

Have at it!


  1. Nice idea, and a nice review. Their website needs some work. I was unable to find any specifics about what precisely they have on offer.

    No need for you to worry about getting a unit. Given the prominence of your review on their facebook page, I suspect your order will be a priority!

  2. Ohhh, Lyndon. Take what they say with a big grain of rock salt. This stuff has been sold in Europe for quite a few years with very mixed results and the refrigeration engineers I know have not had a great experience.

    Mike Holm

  3. I'm not an engineer. I'm wary since HVAC stands for heat vent air-condition; can it be true that no-one in that industry thought of gaining heat from exterior ambient air? especially when in the winter we winterize our idle central air units -why aren't we instead getting them ready to suck heat from our Ontario winter, via the refrigerant gas/liquid in their lines? The panels seem to be the new aspect of this but given the explanation provided it appears that a set of black refrigeration coils might do the same thing. Also, on their website they equate a solar pv system with a solar thermal system, comparing watts for watts (btu's transposed into watts -which is certainly doable). In this they make no mention of it being apples to oranges. They show price vs watts for the two 10kW systems, pointing to the efficiency of the SunPump system. Okay... but their product results in heat energy being produced -not electricity, ie not the same form of energy. Its certainly interesting and seems to hold promise but I want to speak with some engineers before taking one step closer.

  4. Well friends, some time has passed since I wrote that blog entry and I've come to have some grains of salt thrown into the mix on the Sunpump. I still think there are some great aspects to the overall topology/strategy, but there are also some doubts that need to be addressed or possibly shown to be overcome. As some others have hinted, there may be some inaccuracies in this article. First, independant testing results may not yet be available. COP numbers are for when the sun is shining, and otherwise they are lower, like 2.5. And resistance to ice build-up is something we need to see more results on as well.

  5. Another point is this system is really optimized for heating. For cooling, the Sunpump strategy does not present any advantages that I can see, unless you want to cool at night only. AFAIK Sunpump uses an additional outdoor unit for cooling.

    1. Any more info since this last blog back in January?

    2. Any more info since this last post back in January?

    3. I installed an 8.4 kW Sunpump in 2015 in combination with a 3 Ton Geothermal Heat pump. My Geothermal HP is tied to two 1700 gallon water cistern tanks buried in my back yard. The two systems work very well together to both heat and cool my 2,000 SF home in MA. If you want more details in the design and how the system works you can email me at Kevin Fetzer