compressor for wind powered heat pump

[tomwol]

The first thing I should say is I am not a refrigeration engineer but need your advice on a project for a wind powered heat pump I would like to construct for a house in the UK.
I hope that some of you here may be familiar with heat pump technology for creating heat rather than cold?
Could any one recomend a suitable compressor to be directly driven off a small domestic wind turbine. It needs to work at variable speeds and be not too difficult to start up from stationary. It will be used to heat a water resevoirs under the floor of the building as background heat in a very windy location.
Any suggestions? or advice about where I might find technical advice would be greatly appreciated.
Many Thanks
Tom

[taz24]

Could any one recomend a suitable compressor to be directly driven off a small domestic wind turbine. It needs to work at variable speeds and be not too difficult to start up from stationary. It will be used to heat a water resevoirs under the floor of the building as background heat in a very windy location.
Any suggestions? or advice about where I might find technical advice would be greatly appreciated.
Many Thanks
Tom

Wow what a project.
I'm a fan of heat pumps.
Are you wanting to run the compressor directly from the turbine? Using belts or direct on? The biggest problem I see with this is the starting torque and then the fluctuation in power output.
Also the practicalities of mounting the comp.
If your fan is high enough up to catch the wind how do you connect to the comp and if the fan needs to rotate so it can catch the direction of the wind then your compressor would not be able to move because of the pipes that attach.
You could transfer your drive veritcaly and then use gears to transmit the drive to the comp.

Most direct drive comps rotate at 1400rpm but belt driven comps rotate slower, maybe 500rpm.

The variability of the fan will be a problem because as a rule we like constant control to the comp so we can get constant out put.

There is a lot to think about and it sounds like a good project. I'll let others offer their two-peneth worth and lets see if you get some answers to your question.

Good luck
Cheers taz.

[DVaider]

Hi, Tomwol. I think you should drive your compressor non-directly from wind; you should use electric power reciever (I don't know how does it discribes exactly, but I think you understand me;) ). It should generate an electric current after recieving necessary quantity of energy.

[The Viking]

Now this brings old memories back.

I did something similar in a stream many moons ago (direct-hydro-heating!).

Your best bet is to opt for an old open type compressor, Bitzer is the manufacturer that springs to mind but I'm sure there are others out there (these are the ones with a "fly wheel" on the side of them - normally they are belt driven).

As previously mentioned you will need to get the rotary motion down to ground level some how but this shouldn't be a big issue if you use 2 bevel type gearboxes.

The high starting torque will be something to consider, but it could be minimised by fitting some sort of off-loader (a solenoid valve between the suction and the discharge)

When it comes to RPMs, don't worry too much about it.
You will lose performance by running the compressor slow BUT HEY, your power source is free.

[The MG Pony]

Even a car A/C compressor will work well, and with a nice big evap should be a good low compression ratio.

[The Viking]

Now there's a good Idea!
Even if their duty are low, it would be easy to use a couple of them and then sequence their start-up.
You could even modulate the duty and allow even light winds to produce (limited) heating.(For this option I suspect that you will need completely separate refrigerant circuits for each compressor in order to maximise the part load efficiency).

BTW, where about are you based?

[The MG Pony]

Now there's a good Idea!
Even if their duty are low, it would be easy to use a couple of them and then sequence their start-up.
You could even modulate the duty and allow even light winds to produce (limited) heating.(For this option I suspect that you will need completely separate refrigerant circuits for each compressor in order to maximise the part load efficiency).

BTW, where about are you based?


The real beauty is you can let the blades spin up with a fly wheel then engage the clutch so start up is of no issue.

[Capt'n Fixit]

Hello everyone I have been very interested in this technology driving a compressor of sorts to power a refrigeration system to heat a water reservoir have there been any further developments
:cool:

[Karl Hofmann]

Ha!! MG Pony beat me to it..:D A number of car aircon compressors could be run off one fan and the number could be engaged to select required duty and to suit wind conditions... Just add 12 Volts.. Years ago I did consider using a water wheel to power the heat pumps... but I couldn't afford to buy anywhere near flowing water..:(

[Sunsetman]

Hi, for the last year we put in radiant in floor heating on 3 floors of this old house with a geothermal ground source heat pump. This place always has a breeze and some great wind days. My brother has a heating and air conditioning company and I told him last week that I believe I have an idea for a vertical wind mill which i want to heat our water tanks with(we have 3 hot water tanks just not using the elements, our heat pump gives us all our heat and hot water). I asked my brother if we could make or buy a heat pump that is directly driven by a windmill. His comment I'm sure was similar to The Viking's idea of the old open type compressor. My brother has in floor heating in his huge workshop and he is also pretty hot to use wind. My goal is to have my system up and running by the end of next summer. I have just started searching the net for more ideas. My background is electrical design (automation). My belief is that a directly mechanical drivend system would have much less losses then converting to electrical. I am hoping in the next couple of months to get a good design for this system. I am also hoping to share ideas with others, thankyou.

[Gary]

Ha!! MG Pony beat me to it..:D

I'm thinking he beat us all to it. :D

A standard heat pump coupled with an automotive A/C compressor would seem ideal for a wind driven system. In an automotive system variations in speed are handled by engaging/disengaging a magnetic clutch to maintain a set low side pressure. I'm thinking this might be better controlled by compressor shaft speed for a wind system... or perhaps a second (lower setting) low pressure switch for heating mode.

[Capt'n Fixit]

ok well i have got a few things together after a lot of trial and error i have got on to something i am using a "southern cross" waterpump windmill to drive a rotary shaft coupled to a car airconditioning compressor and a car altenator this has overcome the starting torque problem and seems to work as an air compressor very well i havn't hooked a refrigeration circuit yet need a few more trials as the whole thing is pretty ugly at the moment i will keep everyone posted.

[garrymile]

I have just joined this forum and, having recently built a house in Ireland, I am interested in Capt'n Fixit's set-up.

I have now built a 7,000 gallon external tank which will be highly insulated, as I intend to heat it with solar (not your conventional solar panels but something much cheaper and larger) in summer and use it in my ufh system for part of the winter at least. Where I am is quite exposed and we get a lot of wind so I have been looking around for ways of using the wind to boost the tank heat as I think generating electricity is much kess effiicient.

This tank will also be used as a pre-heater for cold water supply to the domestic hot water tank, to save on energy in heating up from cold. That way all the energy generated is useable

Would be very interested in how it's going. I am in Co Wexford.

[Frikkie]

I have seen a wind driven compressor setup many years ago but I never saw it actually working. They used a 1hp bitzer and had a very heavy flywheel on the shaft to absorb some of the torque variation I assume. They used it for making ice with.

[Tim Rowe]

Hi, I just joined so I could post a hello from West Cork. Any news on your project? I'm developing a low-cost windmill for just this type of application and would like to hear of your experiences. Tim

[Capt'n Fixit]

Failed at this stage and lost a bit of interest over the Christmas break have to get back into the work shop and experiment a bit more. The amount of energy required to drive both the alternator and the compressor when pressurized exceeded the fan's capabilities just an engineering problem. I am now thinking about using induction/eddy currents to make the required heat with magnets sitting in some sort of cylinder any ideas??? :o<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

[jgroberson]

This is my first post to this forum so I hope it's correct
I too have followed wind on the net for sometime now
looking for methods to use wind for refrigeration / heat pumps
but found nothing so far but ideas

But there is a gentleman named Hugh Piggot (Google his name)
in the UK I think maybe Scotland that has a massive
website on building your own wind generators
and a sister yahoo group named axial flux where they
tell you how to build everything
His axial flux design alternator actually is a permanent
magnet design with 3 phase ac output then fed into
diodes on the ground to change to dc and charge batteries etc
Some DIY builders are feeding this power to water heater elements
sometimes as a dump load when the batt is full
or direct for heating if no batteries
Yes I know to a refrigeration man that would be COP
of 1 versus COP 3 or better on a belt driven heat pump
but my question to anyone that can advise me
Assuming these 2KW+ wind gens develope 3 phase ac
with varying cycles according to wind speed,
why couldn't they be wired to a 3 phase permanent
magnet motor on the ground to convert tower ac to
mechanical motion on the ground to run hp or anything?
I like the 3 phase water heater idea but I don't know
how varying ac cycles and voltage effects ohms law
as far as resistance and horse power developed
I hope I have given you some ideas to consider
and I hope I can follow your progress

[Capt'n Fixit]

howdy again my once a month log in thank you for Hugh Piggot's details interesting to say the least. the motor being driven off the turbine will not work kinetic, induction and magnetic losses /////////////// wind turbine powered compressor has even more energy loss. A 3 phase electrical heating element may be efficient but the energy is still going from wind (Kinetic) to electrical to heat all with relative losses we need to simplify the process and utilize the energy gathered from the wind in as few steps as possible. Getting away from this forum a bit i think captnfixit@gmail.com is my email

[jgroberson]

[quote= the motor being driven off the turbine will not work kinetic, induction and magnetic losses /////////////// wind turbine powered compressor has even more energy loss. quote]
Captnfixit ,
Yes I know we worry about losses but what if the
energy source is free (ignoring equipment costs)

You're younger than me but I'd swear I can hear when
a refrigeration man's brain gears are starting to turn
We deal daily with converting high priced electricity
to mechanical power then change that to gas/liquid
changes of state to move heat and then educate
ourselves to design the most effecient system
and fans to deliver de-superheated air to the heat source
If you reverse - engineer that process (without the ***** stage) you have a wind generator
Refrig people already know how the cycle works

We humans spend thousands on equipment to heat
and cool our homes and businesses then pay the rest
of our lives for the energy to run it (ignoring equipment costs)

[andrewhall]

Making electricity from wind power means so many transformations of the energy. Mechanical to electrical to chemical back to direct electrical and finally to alternating electrical. With a small wind turbine, there wasn't much energy in the first place. The end AC electrical appliance has to be very small.
Why not drive a Stirling engine as a heat pump direct from a vertical shaft from the blade shaft. A Stirling engine is a heat pump. Stirlings only make small amounts of power - same as a small turbine? A Stirling engine Alpha type has two cylinders - one needs a hot water jacket - the other needs a cold/chiller water jacket.

[tomwol]

Well this is a problem I posted 3 years ago now and then due to perceived technical problems stopped. I am now coming back to it and imagine my surprise when putting in a google search for 'wind powered heat pumps' to find my own thread top of the hits and find all these excellent suggestions. Thanks very much everyone.
Tom

[jgroberson]

Thanks for replying again Tomwol
Your interest and reply prompted me post a question
to the other fellow refrigeration men who have responded to your original wind driven heat pump post
and I hope I'm not hyjacking your post

While attending a small wind conference in Kansas USA
a gentleman told me that some deep sea oil well
platforms actually have a wind driven hydraulic pump
that resembles a small air plane mounted on a pivot
with aileron controls to make the plane go up and down
to create massive hydraulic pressures when the wind
raises and lowers the plane like object
I have not been able to find any links to said applications
here in the flat lands of Kansas USA and I am 1,500 miles
from any off shore oil workers to ask
They might already be driving compressors with
hydraulic motors and wind power

I would like to look at an application
Can anyone share a link or information?

[Gary]

I'm wondering if a variable drive might help:

http://www.houstonbearing.com/pdf/LOVEJOY-VS-PULLEY.PDF

[tomwol]

I have looked into some of the suggestions made, bitzer compressor, stirling engine and auto compressor etc,, But my understanding only goes so far. What I really need is an engineer to help, either to instal or to specify the system.
The project is based in Dungeness, Kent, UK.
Would like to know more about the stirling engine too.
Tom

[mad fridgie]

Like most you are starting at the wrong end.
How much refrigeration heat of rejection do you want each day.
To what temperature do you want to heat the water.
What is your main source of energy (air, ground, water)
Now you have a refrigeration profile.
What is your daily average wind speed (min and max)
Now you can determine the run hours per day.
Now we have a load profile.
From said set of conditions we can work out shaft power required for the compressor.
Then add losses for gear box /transmission.
Now we have shaft power for the turbine. (how big it needs to be)
Can it handle the max speed? (both turbine and comp)
How do you control it when required set points are reached (max SCT for the comp)
When you have done this you can determine which type of comp is best suited.

[mad fridgie]

If you want to keep it really simple and it is just heat energy that you are after, just stick some blades onto you wind powered shaft and place into a baffled tank of water!
"heated water", self balancing!

[MikeHolm]

Don't know if anyone is still looking at this thread but reading through from the beginning I was thinking of a CVT transmission (check out Nissan) to keep a more constant mechanical speed for the compressor (whichever one is used) but Gary beat me to it.

Also look at the old Jacobs wind chargers, many of which were used for water pumping and there are thousands of them all around the US of A and Canada and could be hooked up directly to the CVT.

One could also integrate a PV/battery/DC motor system onto the wind shaft with a clutch to augment the wind power. Great speculative thread.

[saabnut]

I would suggest using a variable displacement automotive compressor, in addition to a flywheel.

[AndyA]

Size the wind blades large enough to provide enough power at low wind speeds. Then tilt the blades at an angle to the wind when you need to reduce power because of strong winds.
The Hugh Piggot design has an very simple way to do this by offsetting the axis of the blade to the tower pivot and providing a pivotable tail. The push of the wind gets balanced against the gravity of the tail. In a strong wind the tail folds up and the blades turn crosswind. (Yeah a picture *is* worth 1000 words).

I would try to avoid any sort of transmission. This is going to increase the cost, waste energy, and hurt reliability. Design the blades to suit the RPM and torque you need for the compressor. Few thin blades for high rpm, but lower torque. Many thicker blades for lower rpm, but higher torque. You'll also need to set the pitch of the blades to work at a particular RPM to wind speed. Highly pitched blades will want lots of wind speed for a given RPM. Shallow pitched blades will want lots of RPM for a given wind speed.

With a simple orifice the pressure should equalize when the compressor isn't running. This means there is no startup load (other than friction). There won't be any pressure difference across the compressor until it gets up to speed.

[eiffel]

Hi, i am working in heat pump factory, if you need my help, please feel free to contact me.

[Kompulsa]

Hello.

A similar idea crossed my mind in the past, but that was to use the electricity generated by a traditional wind turbine to power a compressor.

If you are willing to spend the money on 1 (or two) batteries and a DC to AC inverter to power the compressor. you can use the wind turbine to charge the one or two batteries (depending on compressor size) that would act as a buffer for the wind power so you could actually provide the compressor with a non-varying power supply for an hour at a time, longer than that, or even less than an hour depending on what you would rather do. Basically, the compressor would turn on and heat for an hour using the battery charged by the DC generating wind turbine (most are DC), then the battery (ies) would supply DC to the inverter, and the inverter 120 0r 240 volts A/C for the compressor. :)

This way, you won't need a variable frequency drive compressor (no speed control of the compressor is required at all), you can use an ordinary cheap compressor that cycles on and off when the batteries are charged. You will need a circuit that will turn the compressor on when the battery charge exceeds a certain level, though, and many inverter models will automatically shut it off when there is an energy shortage.


The first thing I should say is I am not a refrigeration engineer but need your advice on a project for a wind powered heat pump I would like to construct for a house in the UK.
I hope that some of you here may be familiar with heat pump technology for creating heat rather than cold?
Could any one recomend a suitable compressor to be directly driven off a small domestic wind turbine. It needs to work at variable speeds and be not too difficult to start up from stationary. It will be used to heat a water resevoirs under the floor of the building as background heat in a very windy location.
Any suggestions? or advice about where I might find technical advice would be greatly appreciated.
Many Thanks
Tom

[shooter]

buy a bock or bitzer open compressor.
make a system of it with propane gas (R290)
and an electronic expansion valve ( a simple motor driven needle valve)
cheap and easy.
if you open the expansion valve the compressor will start working.
if wind is low just close the valve a little and the capacity will lower.

[uncle-flo]

I'm new here. I have researched this topic many times before with no luck. Google must be doing a better job theese days as I see the thread has been a few years in the making.
I too would like to drive a heatpump with a wind turbine. The major part of the plan is to use seasonal heat storage with the use of boreholes. I would heat the earth with solar collectors & air to water heat exchangers during the summer and recover the heat from the store using a heatpump system to boost the water temp to about 120 degrees F. My research leads me to believe that with a properly constructed, four bladed turbine of 20' dia I should be able to capture about 7500 watts (10 hp) of energy in a 20 mph wind. I would mount the propeller to a right angle gearbox atop the tower with a gear ratio of about 1:5. A vertical driveshaft would follow down the mast to another right angle gearbox near ground level. This gearbox would have a ratio of about 1:3. Now with the prop turning at 120 rpm my horisontal shaft at the ground would spin at 1800 rpm. My plan is to belt drive SEVERAL automotive AC compressors from this shaft. I would have one compressor coupled to the shaft at all times and have the others come online using the 12 volt magnetic clutches as the wind speed increases. To this point I'm sure I can make that much of the system work.
Now here's some questions for the HVAC experts.
1) Would there be a problem having a variable number of compressors all pumping into a common condenser, expansion valve and evaperator?
2) What type of expansion valve could I use to accomidate the variable volume of refrigerant? ( hopefully there is one that would adjust automaticly)
3) I plan to use propane (R290) Is there a way to dry bar-b-q gas to make it suitable?
4) Would CO2 work as a purge gas?

OK folks. Tear this apart and tell me where I'm going wrong. All comments will be greatly appreciated.
Uncle-flo