Solar powered heat pump

[Gary]

As I understand it, inverter driven heat pumps convert AC to DC and then back to AC. I'm wondering if the DC output from solar panels could be added to the mix in the middle of this transition.

Possibly the solar panel DC output could feed back into the AC grid when the heat pump isn't running... thus eliminating the need for the DC to AC solar inverter.

It seems like integrating solar with a heat pump would be a very good thing.

[Bigfreeze]

Its already being done all over europe Gary. Half of Germany have their PV array interlocked with their heat pumps. Theres even a distribution system (Emma its called) which decides when it should feed the house and when it should feed the grid. We've just recently being researching adding PV to our list of supplied products to compliment our HP's

[Gary]

Really? Seems I'm behind the times.

Got any links?

[MikeHolm]

It would make more financial sense where there is no generous FIT. Where I am you are better off to sell everything to the grid. I think it would work well in the States.

[Gary]

I've done some reading about the FIT programs. It sounds very much like a license to steal...and a recipe for economic meltdown.

[desA]

I have heat-pumps operating : solar PV - battery - inverter - heat-pump.

Some of these in rather interesting applications.

[MikeHolm]

I've done some reading about the FIT programs. It sounds very much like a license to steal...and a recipe for economic meltdown.

Regardless, they are what allowed the PV industry to grow and for prices to get as low as they are now. Without them, it wouldn't have happened. The FIT where I am adds at most 1% to the cost of electricity. If people paid the true price for power, without any subsidy to any industry, we wouldn't need the FIT or any other incentive.

But that is not your case in Florida and I suspect, with your solar resource, you could offset a lot of the power needed by your HP even by an annual net metering plan.

[MikeHolm]

I have heat-pumps operating : solar PV - battery - inverter - heat-pump.

Some of these in rather interesting applications.

Do you have an example of a good system? what happens when there isn't enough stored power?

[Gary]

Regardless, they are what allowed the PV industry to grow and for prices to get as low as they are now. Without them, it wouldn't have happened. The FIT where I am adds at most 1% to the cost of electricity. If people paid the true price for power, without any subsidy to any industry, we wouldn't need the FIT or any other incentive.

But that is not your case in Florida and I suspect, with your solar resource, you could offset a lot of the power needed by your HP even by an annual net metering plan.

The biggest problem I have with all of the subsidy programs is that they subsidize the energy seller rather than the energy buyer. It makes much more economic sense to subsidize the energy buyer, simply because they pay the higher rate therefore their payback period is shorter. Ideally, I would like to see the energy utility company become the energy storage company.

Eventually solar costs will drop to the point where subsidies are not needed. At that time it will still make more sense for the energy buyer than it does for the energy seller... simply because they pay the higher rate.

The city of Gainesville Florida has a FIT program in place. It started off with the cost to ratepayers being 1%, but has quickly grown to 2%. The costs are locked in for the length of the contracts and are therefore cumulative. The more capacity is added, the more the costs grow. They hold down the cost increases by limiting who can participate in the program and how much capacity they can install. It is indeed a license to steal. Crony capitalism at its finest.

Any strategy which adds to energy costs adds to the price of all products and services, lowering the standard of living for all and making all products and services less competitive... especially in energy intensive industries. Rising energy costs are not a good thing.

[Gary]

I have heat-pumps operating : solar PV - battery - inverter - heat-pump.

Some of these in rather interesting applications.

Can you provide a little more detail? Perhaps wiring diagrams?

It would make no sense to convert DC to AC to DC to AC. What I had in mind was to, as directly as possible, power the heat pump compressor from the solar panels.

[Bigfreeze]

Regardless, they are what allowed the PV industry to grow and for prices to get as low as they are now. Without them, it wouldn't have happened. The FIT where I am adds at most 1% to the cost of electricity. If people paid the true price for power, without any subsidy to any industry, we wouldn't need the FIT or any other incentive.

But that is not your case in Florida and I suspect, with your solar resource, you could offset a lot of the power needed by your HP even by an annual net metering plan.

Do you bother with PV Mike. If so what panels are you using.


I think all heat pumps would need to be fed AC Gary and let the invertor convert to DC otherwise you'll end up in problems where the available power from the PV is insufficient and you could't run the HP. Startups would also be a problem and without the invertor speed drive would also be eliminated.

[MikeHolm]

I do a lot of PV because there are no subsidies here for solar thermal, since 2010, and our gas and power costs are artificially low so the payback for thermal is 15+ years.

The Ontario FIT program requires that inverter, panel and racking manufacturers make a portion of their products here. The govt decided that if there was to be ratepayer money going to promote solar, the manufacturing jobs need to be here too. The panels we use are made here but some are subsidiaries of Spanish, Chinese or German companies.

Helios, from Spain has a joint venture as well as Canadian Solar (which is more Chinese than Canadian) but I know which ones are good and which ones are not so good. Somewhere I have a list of the top tier product in Europe which I will post.

[MikeHolm]

Do you bother with PV Mike. If so what panels are you using.


I think all heat pumps would need to be fed AC Gary and let the invertor convert to DC otherwise you'll end up in problems where the available power from the PV is insufficient and you could't run the HP. Startups would also be a problem and without the invertor speed drive would also be eliminated.

I think you would need to have an abundance of battery storage if you wanted to supply power on the DC side and that can be expensive plus if it is an inverter driven comp with a DC motor, the voltage will be all over the place so that has to be accounted for. There are a couple of US companies that advertise heat pumps with PV and I think they just add a tie in and feed the power to the grid, but I could be wrong in this.

[Bigfreeze]

I think you would need to have an abundance of battery storage if you wanted to supply power on the DC side and that can be expensive plus if it is an inverter driven comp with a DC motor, the voltage will be all over the place so that has to be accounted for. There are a couple of US companies that advertise heat pumps with PV and I think they just add a tie in and feed the power to the grid, but I could be wrong in this.

Thats the way most would do it this side of the drink. PV feeding the mains board and supplimenting the HP or else feeding the grid directly.

At least the Canadian Government has some foresight. I've been advocating we should do that with wind energy here for years. Ask Siemens etc to establish massive windfarms off the west coast but insist they manufacture all the turbines here. Couldn't do the same with PV in the domestic sector due to EU competition rules. For a country of our size and population we should be virtually 100% green. Biggest marketing opportunity in history. The Emerald Isle-100% green

[MikeHolm]

The biggest problem I have with all of the subsidy programs is that they subsidize the energy seller rather than the energy buyer. It makes much more economic sense to subsidize the energy buyer, simply because they pay the higher rate therefore their payback period is shorter. Ideally, I would like to see the energy utility company become the energy storage company.

Eventually solar costs will drop to the point where subsidies are not needed. At that time it will still make more sense for the energy buyer than it does for the energy seller... simply because they pay the higher rate.

The city of Gainesville Florida has a FIT program in place. It started off with the cost to ratepayers being 1%, but has quickly grown to 2%. The costs are locked in for the length of the contracts and are therefore cumulative. The more capacity is added, the more the costs grow. They hold down the cost increases by limiting who can participate in the program and how much capacity they can install. It is indeed a license to steal. Crony capitalism at its finest.

Any strategy which adds to energy costs adds to the price of all products and services, lowering the standard of living for all and making all products and services less competitive... especially in energy intensive industries. Rising energy costs are not a good thing.

There is no perfect system, Gary, and all incentives cost someone, somewhere for some period of time. The question is whether the benefit outweighs the cost. Germany started with a FIT that was around $.80/kwh and now it is down to $.0 and the industry is still going strong, partly because power costs are higher anyway and partly because there is a common understanding that it was worth the cost.

Gainsville is probably a bit too small to do this by itself but in a heavy power consuming state like Florida there needs to be some program. Is it stealing if a democratically elected govt makes a program that the majority of people agree with? I see people complaining that Obama has not held down the price of gasoline and that he should be booted out for that reason. No one can do that. There will be increases in all fuel costs for many reasons so shouldn't we be doing something to look farther down the road?

[MikeHolm]

Thats the way most would do it this side of the drink. PV feeding the mains board and supplimenting the HP or else feeding the grid directly.

At least the Canadian Government has some foresight. I've been advocating we should do that with wind energy here for years. Ask Siemens etc to establish massive windfarms off the west coast but insist they manufacture all the turbines here. Couldn't do the same with PV in the domestic sector due to EU competition rules. For a country of our size and population we should be virtually 100% green. Biggest marketing opportunity in history. The Emerald Isle-100% green

Ireland is a bit small to support a complete manufacturing line unfortunately but there must be ways the govt can steer some mandatory component manufacturing there. In Canada when the big wind boys came in (Vestas and Siemens etc) they only made the towers here. Eventually more was made here but it took time.

Don't confuse the government of Canada, which does not believe in global warming or any environmental program with the provinces such as Nova Scotia or Ontario, which do. All positive efforts come from the provinces and there is no leadership at all from the Federal govt. I am really pissed off about this.

[Gary]

If we are going to subsidize, this should be done in the most cost effective way. This gives us maximum impact for the money spent. Solar is more cost effective for energy buyers than it is for energy sellers, because the energy buyers are paying the highest rate.

Of the energy buyers, it makes most economic sense for the residential customers... and for the residential customer it makes the most sense to only subsidize as much capacity as he can use.

This is how we get the biggest bang for the buck... by subsidizing solar panels on millions of residential rooftops, not by subsidizing massive 'for profit' solar farms. As an added bonus, this also loosens the stranglehold that utilities have on their customers... and the job creation potential for residential solar installers is enormous.

[Bigfreeze]

If we are going to subsidize, this should be done in the most cost effective way. This gives us maximum impact for the money spent. Solar is more cost effective for energy buyers than it is for energy sellers, because the energy buyers are paying the highest rate.

Of the energy buyers, it makes most economic sense for the residential customers... and for the residential customer it makes the most sense to only subsidize as much capacity as he can use.

This is how we get the biggest bang for the buck... by subsidizing solar panels on millions of residential rooftops, not by subsidizing massive 'for profit' solar farms. As an added bonus, this also loosens the stranglehold that utilities have on their customers... and the job creation potential for residential solar installers is enormous.

I agree. I think that every single new house should have to cover its own energy needs either by PV or wind and that existing houses be incentivised to do the same. Government should be subsidising this as it will save on penaltys for over runs on C02 credits and also the cost of upgrading power lines and building new power stations.

Wasn't there a case of a state in the US recently which banned all products that were not A rated and heavily subsidised the purchase of new equipment as it was cheaper than building a new power station. A boon for local shop owners also to get the money flowing again.

We probably couldn't sustain the entire manufacturing process Mike but we have possibly the biggest wind resource in the world off our west coast and an area which has very little maritime traffic so theres certainly a huge potential for this country to become a net exporter of power.

[Gary]

I would stop short of requiring new homes to have alternative power. I would require them to be wired for alternatives... such that alternative sources could later be simply mounted and plugged in.

[frank]

I would stop short of requiring new homes to have alternative power. I would require them to be wired for alternatives... such that alternative sources could later be simply mounted and plugged in.

How do you know at this stage what sort of wiring future technologies need?

[MikeHolm]

I don't think power wiring is going to change so much that the technology of the day 10 years from now cannot be connected with todays wiring.

[MikeHolm]

Here is a neat article on the cost to the tax payer of solar in the US compared to Germany. Its a web thing so I don't know if the page will last.

http://www.renewableenergyworld.com/...October27-2012

[Bigfreeze]

I do a lot of PV because there are no subsidies here for solar thermal, since 2010, and our gas and power costs are artificially low so the payback for thermal is 15+ years.

The Ontario FIT program requires that inverter, panel and racking manufacturers make a portion of their products here. The govt decided that if there was to be ratepayer money going to promote solar, the manufacturing jobs need to be here too. The panels we use are made here but some are subsidiaries of Spanish, Chinese or German companies.

Helios, from Spain has a joint venture as well as Canadian Solar (which is more Chinese than Canadian) but I know which ones are good and which ones are not so good. Somewhere I have a list of the top tier product in Europe which I will post.

Did you happen to lay your hands on that list Mike. Which panels would you prefer to work with?

[Gary]

Here is a neat article on the cost to the tax payer of solar in the US compared to Germany. Its a web thing so I don't know if the page will last.

http://www.renewableenergyworld.com/...October27-2012

A good example of how figures lie and liars figure. For starters there is no accelerated depreciation for homeowners, thus the ''tax benefit @ 55%'' is actually @ 30% for residential. It is $1.50, not $2.75... which brings the ''unitized tax benefit'' down to 0.071.

Further, as both taxpayer and ratepayer I get to pay the utility $.06/kWh to install the panels plus $.12/kWh for the electricity... for a total of $.18/kWh.

[Gary]

You can get all of the materials needed for about $2.25/W retail. Obviously, @ $5.00/W most of it is labor and profit.

Westinghouse has a new self-contained expandable grid-tied system they market through Lowes for about $2.72/W that addresses the labor costs. The inverter is built into the panel. The panel is easy to mount and you just need to run a 230V cable down to a breaker in the electrical panel. Flip on the breaker and 5 minutes later it starts generating.

http://www.lowes.com/pd_372806-15399...kit&facetInfo=

[MikeHolm]

A good example of how figures lie and liars figure. For starters there is no accelerated depreciation for homeowners, thus the ''tax benefit @ 55%'' is actually @ 30% for residential. It is $1.50, not $2.75... which brings the ''unitized tax benefit'' down to 0.071.

Further, as both taxpayer and ratepayer I get to pay the utility $.06/kWh to install the panels plus $.12/kWh for the electricity... for a total of $.18/kWh.

Why are you paying the Utility for anything to do with solar? We have a $5 per payperiod billing fee and that is it....then they pay me. I don't understand your system.

Now you are going to make me go back and read that article again DUH.....

[MikeHolm]

You can get all of the materials needed for about $2.25/W retail. Obviously, @ $5.00/W most of it is labor and profit.

Westinghouse has a new self-contained expandable grid-tied system they market through Lowes for about $2.72/W that addresses the labor costs. The inverter is built into the panel. The panel is easy to mount and you just need to run a 230V cable down to a breaker in the electrical panel. Flip on the breaker and 5 minutes later it starts generating.

http://www.lowes.com/pd_372806-15399...kit&facetInfo=

Westinghouse just licensed their name to a chinese company for these panels, they are for sale here too. They are also just packaging a micro inverter with each panel which is what we do with panels anyway. Westinghouse is not a Tier1 manufacturer. That cost does not include a lot of stuff like wiring, disconnects, breakers, labelling, some racking components particular to your roof, permits etc.

[MikeHolm]

Did you happen to lay your hands on that list Mike. Which panels would you prefer to work with?

My all time favorite is Schott. I've been to their plant and I have a lot of respect of them as a company. Really good quality. After that, Conergy, Sovello, Solarworld, REC, Helios, Q-Cells (now Hanwha)

I'm not too fond of the Chinese stuff but some of it is quite good such as Suntech, Trina, Yingli, Canadian Solar.

My favorite inverters are SMA (Sunny boy) and Fronius as well as Dorfmuller for micro-inverters. We've used a lot of Enphase micro-inverters as well but there are others coming on the market now.

Hope that helps.

[Gary]

Westinghouse just licensed their name to a chinese company for these panels, they are for sale here too. They are also just packaging a micro inverter with each panel which is what we do with panels anyway. Westinghouse is not a Tier1 manufacturer. That cost does not include a lot of stuff like wiring, disconnects, breakers, labelling, some racking components particular to your roof, permits etc.

Nonetheless, the Westinghouse panels require far less labor and less skill to install. The 20 panel set comes to 4.7kW. At an installed price of $5/W that would bring the total to $23500 minus let's say $13500 for materials, permits, etc. leaving $10000 for labor/profit.

Kinda makes sense for DIYers, don't you think?

As a homeowner, would I be willing to pay someone $10000+ to mount 20 panels and run a 230V line up to the roof? I don't think so. And I'm betting the contractor can get all of the materials for a lot less than $13500.

Do contractors really charge $5/W installed? I'm thinking they could make a very good profit at $3.50/W installed... and that would bring the unitized tax benefit down to .0494

[Bigfreeze]

My all time favorite is Schott. I've been to their plant and I have a lot of respect of them as a company. Really good quality. After that, Conergy, Sovello, Solarworld, REC, Helios, Q-Cells (now Hanwha)

I'm not too fond of the Chinese stuff but some of it is quite good such as Suntech, Trina, Yingli, Canadian Solar.

My favorite inverters are SMA (Sunny boy) and Fronius as well as Dorfmuller for micro-inverters. We've used a lot of Enphase micro-inverters as well but there are others coming on the market now.

Hope that helps.

Thanks Mike

[MikeHolm]

Nonetheless, the Westinghouse panels require far less labor and less skill to install. The 20 panel set comes to 4.7kW. At an installed price of $5/W that would bring the total to $23500 minus let's say $13500 for materials, permits, etc. leaving $10000 for labor/profit.

Kinda makes sense for DIYers, don't you think?

As a homeowner, would I be willing to pay someone $10000+ to mount 20 panels and run a 230V line up to the roof? I don't think so. And I'm betting the contractor can get all of the materials for a lot less than $13500.

Do contractors really charge $5/W installed? I'm thinking they could make a very good profit at $3.50/W installed... and that would bring the unitized tax benefit down to .0494

It is $5/w here...roughly. Really it depends on other factors as well such as permit costs and access fees. Some utilities won't let a home owner do it themselves. Plus there is liability and workmans insurance and labour warranty. I know in Germany it is about $4/w but financing and approvals are done over the phone with little or no paperwork.

[Gary]

It is $5/w here...roughly. Really it depends on other factors as well such as permit costs and access fees. Some utilities won't let a home owner do it themselves. Plus there is liability and workmans insurance and labour warranty. I know in Germany it is about $4/w but financing and approvals are done over the phone with little or no paperwork.

I suspect that the people who throw obstacles in the path of would-be solar customers and those who advocate solar subsidies are one and the same... and they don't see the contradiction. You would think they would want to make it easier/cheaper, not more difficult/expensive.

[Gary]

Westinghouse just licensed their name to a chinese company for these panels, they are for sale here too. They are also just packaging a micro inverter with each panel which is what we do with panels anyway.

They also integrate the racking system, which is a big part of the installed cost.

[MikeHolm]

Racking on a sloped roof is usually around $.60/w. They assume everything is flat and inline. If you have a convoluted roof you will need more specialized wire and the MC4 connectors and a special tool to put them on. It isn't a huge deal but it takes some knowledge and parts.

The Enphase inverters that come with the panels use a trunk cable with specific spacing between the connectors so the panels must match the cable layout. Also, I didn't see the #6 ground wire included that must be run from each inverter and bonded to each panel.

That said, if you have a straight sloped it relatively easy.

I think the regs are put in place partly by bloody lawyers and partly by utilities that don't really want to be a part of distributed generation. Most of them a very happy dealing with a few bigger corporate power producers. If I was them, I would hate dealing with a bunch of homeowners.

[Gary]

The installation seems fairly straightforward:

http://pdf.lowes.com/installationgui...39_install.pdf

No doubt, it would be better to have the panels professionally installed and a simplified integrated racking system should make it easier for the professionals as well as the DIYers, which should result in lower installation costs.

As I understand it, the PV panels are no longer the largest part of the installed cost and the trend now seems to be focused on reducing the installation costs.

[Gary]

I think the regs are put in place partly by bloody lawyers and partly by utilities that don't really want to be a part of distributed generation. Most of them a very happy dealing with a few bigger corporate power producers. If I was them, I would hate dealing with a bunch of homeowners.

Unless/until the utilities find a way to profit from energy storage, they are not going to get excited about it.

Hmmm... possibly the net metering laws could be altered to where the utility does not pay for excess generation.

[Gary]

Clearly the key to all of this is installed cost. Once the cost drops to a point where subsidies are not needed, everyone will want to go solar.

I have crunched the numbers for my area and calculate that the magic number, without subsidies, for a 10 year payback would be about $2.35/W installed.

Given our 30% tax rebate, the magic number with the subsidy would be $3.35/W installed.

Solar costs have been dropping at a rate of 15%/year, with the cost cut in half every 3-4 years, so if this trend continues, we are not too far from the goal.

[MikeHolm]

I wouldn't count on prices of panels to come down at the same rate as the last couple of years. There is a glut of panels on the market and it is keeping the prices low. It is expected to last for maybe 1 more year. Maybe the other components will come down a bit more but things like aluminum racking and copper float with the market.

The 10 year payback without subsidy is a dream. The utilities amortize over way longer than that which is why we are not hit with huge increases whenever they have to upgrade the NUC plant so why should we demand a 10 year return?

[Gary]

Real estate experts estimate that energy saving devices add 20 times the first year energy savings to the value of the house. IOW, if you save $1000 in the first year, this adds $20,000 to the value of your house. If this is to be believed, the system immediately pays for itself. I'm not so sure.

[Gary]

Interesting info:

http://www.irena.org/DocumentDownloa...s-SOLAR_PV.pdf

[Gary]

The ten year payback is arbitrary... but that would be enough to peak my interest.

To muddy the water just a little more, if next year's drop in cost exceeds this years energy savings, I am better off waiting until next year.

[MikeHolm]

The ten year payback is arbitrary... but that would be enough to peak my interest.

To muddy the water just a little more, if next year's drop in cost exceeds this years energy savings, I am better off waiting until next year.

Age old question....do I buy it now and help to reduce future prices or do I wait and hope someone else buys so prices come down........
I don't think the costs will come down that much in the short term.

[Gary]

Age old question....do I buy it now and help to reduce future prices or do I wait and hope someone else buys so prices come down........
I don't think the costs will come down that much in the short term.

The IRENA data seems to disagree, projecting drastic reductions in the next few years. Realistically, it pays to wait.

Clearly, solar will continue to be driven by factors other than monetary, such as concern for the environment and/or a desire to reduce dependence upon the blood-sucking utilities.

This could happen. But then, I am still waiting for the environmental advocates to put their money where their mouth is by forming non-profit sales/installation companies.

[Gary]

Clearly, solar will continue to be driven by factors other than monetary, such as concern for the environment and/or a desire to reduce dependence upon the blood-sucking utilities.

You might notice there is something in the above quote for everyone.

While some have deep environmental concerns, there are others of an entirely different persuasion who are philosophically opposed to monopolies and would like nothing better than to thumb their noses at the utilities.

Residential solar is a win/win.

[MikeHolm]

You might notice there is something in the above quote for everyone.

While some have deep environmental concerns, there are others of an entirely different persuasion who are philosophically opposed to monopolies and would like nothing better than to thumb their noses at the utilities.

Residential solar is a win/win.

I'll agree with you there........

[Gary]

I knew we would end up agreeing on something.

[MikeHolm]

BTO as well