Heat Pump components

I am fitting an air source heat pump to a property I am renovating.
It will be about 10 kw
There is at least 6 machines that fit the bill but the components they use vary to the point of confusion.
My question is, if a refrigeration engineer had to chose a heat pump what preferences would he make, from the following.
Refrigeration gas r407c , r417a or r410a
Compressor Toshiba rotary. Copeland scroll or any other
Heat exchanger/evaporator, plate or any other
Manufacturers include;
Dismy
Trianco activair
Aermec
Wharf
Esavep
Sunrich solar
Heatking
And , the prices vary from £1100 to £4500 for the same size?
Does made in China mean poor quality?
You guys knows what works and what lasts!
Any thoughts?

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Originally Posted by mayo

I am fitting an air source heat pump to a property I am renovating.
It will be about 10 kw
There is at least 6 machines that fit the bill but the components they use vary to the point of confusion.
My question is, if a refrigeration engineer had to chose a heat pump what preferences would he make, from the following.

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10 Kw output?? How big is your house?
I would get the property sized correctly because if
you oversize the property it can be very expensive.

Heat pumps work well when they are running in their designed range if it was over sized it would cut in and out and therfore the running costs would increase.

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Originally Posted by mayo

Refrigeration gas r407c , r417a or r410a
Compressor Toshiba rotary. Copeland scroll or any other

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All of the refrigerents stated are good for specific parameters and temp ranges. The choice of refrigerant will be made for you by the design of the heatpump.

Compressors are as reliable as each other, but the rotary type of comp has been around for 80 odd years and has proven to be reliable. The scroll has been around for about 15 years and has yet to prove itself reliable as a longterm low maintenance compressor, you want it to last at least 10 years. Scrolls are excelent though and are very effiecient.

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Originally Posted by mayo

Heat exchanger/evaporator, plate or any other
Manufacturers include;
Dismy
Trianco activair
Aermec
Wharf
Esavep
Sunrich solar
Heatking
And , the prices vary from £1100 to £4500 for the same size?
Does made in China mean poor quality?

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Not heard of anyof those makes.

There are two schools of thought about parts from China.
One is they are patern parts, being as reliable as any other make and lots of known manufactures use chineese parts.
The other is don't touch chineese imports with a barge pole.

It is luck of the draw to be honest. You could pay £1000's more for one over the other and they could both be as reliable or unreliable as each other.

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Originally Posted by mayo

You guys knows what works and what lasts!
Any thoughts?

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Be careful how they sell you the KW output rating to you.
Some machines may appear equal on paper but it is because different manufactures use different standards for quoting KW output.

Cheers taz

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Originally Posted by mayo

Refrigeration gas r407c , r417a or r410a

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R410a

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Compressor Toshiba rotary. Copeland scroll or any other

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Copeland digital scroll

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Heat exchanger/evaporator, plate or any other

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Plate

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Does made in China mean poor quality?

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In most cases (90%).

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You guys knows what works and what lasts!

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Daikin, Gea

Get your property sized correctly and spend your money on a recognised a\c manufacturer!!!

The biggest issue I think all of us have with the Chinese crap, oops, sorry equipment, is the lack of after-sales service/manuals/spare parts/engineers trained on it/training courses.

One trick would be to phone up the UK importer and ask for a replacement control PCB or compressor before you decide what make to go for.

Regarding brand names, there are lots of Swedish/Swiss/German manufacturers out there that made these sort of systems for ages (over there this is old, tried and tested technology. What we are seeing over here at the moment is people trying to re-invent the wheel)

http://www.viessmann.com/com/en
is one example with information in English on their website.

I agree getting it properly sized is important this has been done, taking into consideration all aspects, property type, insulation water demands and future extention etc.
It has under floor heating, with a heat bank and a multifuel back boiler (for the colder winter months if needed) all installed with option for solar if desired.
The only component to fit is the Heat Pump.
I found comparing the output confusing the 10kw rating comparison I used is at 7-10 deg ambient temp with water between 45-55 deg
I also look at the kw input to compare machines usually between 3.6 and 4 kw do you think this is a useful comparison.
Some of the machines are called 14kw but at closer look at spec the ambient temp is 25deg very misleading.
Standards for comparing this type of machine is needed don’t you think.
Aermec and heatking are air-conditioning companies Italian and British £3000 +
Dismy and wharf are chineese companies £1200 ish
Tranco is a large boiler company activair is its move to the heat pump market I think made in china for them £2000 ish
The others are British design made in china £2400 +
Well that’s what I was told.

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Originally Posted by mayo

I also look at the kw input to compare machines usually between 3.6 and 4 kw do you think this is a useful comparison.

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We call that ratio COP (coefieciency of performence)

A normal frigde will give you a COP of about 3 to 1
Which means for every unit you pay for you get 3 units out.

Heatpumps have a higher COP because the compressor input can be added to the combined output so the fridge COP of 3 to 1 becomes a heat pump COP of 4 to 1.

So on your 4KW input at 3 to 1 you have a output of about 12KW and at 4 to 1 you have a output of 16 KW.

So you see, by manipulating the figures a little bit you get a big difference in the end results.

taz.

Have you considered Dimplex or Vallient heat pumps.

taz.

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Thanks Taz
Dimplex look a good machine but are so expensive.

All the designs will be similar and to them you can add the mitsi electric ecodan and daikin altherma units which have the added advantage of inverter driven compressors.
R407C is probably the better choice refrigerant for the lower ambient conditions that you are going to need the unit to operate in.
Check the cop and duty of the unit at the design water temperature and at -5°C to see if the unit will provide any heating at that condition. A few of the chinese models will be cutting corners and the result may be operational limits when you need as much output as posible. remember the lower the ambient the lower the efficiency.
With regards to chinese products some are good some are lousy. Just make sure spares and support are available.
Best of luck
Brit

I m confused with the refrigerants used.
nike123 advises r410a, brit r407c and the machine that i am looking at closest now, uses r417a.
Do they all perform the same if so why so many.
Should i not concider the gas an important factor in choosing and assume the designer knows what he/she is doing.
Mayo

Quote:

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Originally Posted by mayo

I m confused with the refrigerants used.
nike123 advises r410a, brit r407c and the machine that i am looking at closest now, uses r417a.
Do they all perform the same if so why so many.
Should i not concider the gas an important factor in choosing and assume the designer knows what he/she is doing.
Mayo

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R407 is transition refrigerant which is developed to be substitute for R22 refrigerant for components already manufactured because of simmilar pressures. New components are designed for higher pressure and are suitable for future refrigerant R410a which has got better heat transfer than R407C and it is considered as main future refrigerant of air conditioning industry.

I don't think that R417a will have any significant future market share in air-conditioning because that is also R22 replacement as it is R407C.

im just curious, the underfloor heating - has it been installed properly?

the heat pump is a low temperature heating system and the heating circuit must be designed to suit the heating system.

will you be fitting a buffer tank?

as for choice i'd tend to agree with people on here and buy a system that guarantees an after sales service and a supply of spare parts.

personally, and this is just through personal preference i'd go with a system from alpha innotec.

The underfloor heating is installed using john guest fittings
pipe at 150mm spacing in screed
250lt heatbank

Hi,

I am using a brazed plate heat exchanger (for heat pump), and now I am considered on refrigerant mass in the system.
The question is: Is a liquid reciver necessary for the system, and on what reference have I to calculate a mass of refrigerant in the system?
Have anybody any ideas on that ?
Thank you.

Remember you get what you pay for, so no matter what you pay a high price, the question is will that high price be a one shot while it puuurs away or will it be the cost of the service man every year or more?

I am using a brazed plate heat exchanger (for heat pump), and now I am considered on refrigerant mass in the system.
The question is: Is a liquid reciver necessary for the system, and on what reference have I to calculate a mass of refrigerant in the system?
Have anybody any ideas on that ?
Thank you.

We use plate heat exchanger too.
Plate heat exchanger can only contain a little refrigerant, and the working conditions vary a lot, so a high pressure receiver is necessary. If a high pressure receiver is used, the mass of refrigerant maybe more than that the refrigeration system has no receiver.
Every model compressor recommend the refrigerant mass charging .

I am a chinese refrigeration engineer.

Some chinese products are good, some are lousy. It is true.
Maybe it is the same for other country's products. Every country has good products ,and at the same time has rubbish products.

Thank you, yangchenchen. What about oversurfacing of heat exchanger, as I know in that case receiver is not necesary to use. Any ideas, or sugestions on that? Thanks.

And how conditions will change in system without liquid receiver and with it?

There are some more differences between R407c and R410a.
R417 I don't know! R410a has a higher specific volume compared to R22 and R407c at the compressor suction.
R410a also "absorbs" heat better than R407c. And last, but not least, R410a has a higher pressure at low temps compaired to the others.

are you looking at air to air.
if so you should use a 5mxs90e.
air to water use an Altherma ERHQ8 - 11.
at least it will be something reliable..

i am against the opion "made in china means poor quality", it had been true ten years ago. Now many chinese products turn out very good. (eg. the check valve we make surpass Danfoss in a recent test) Many big companies (ThermoKing, York, Carrier) have got away with the idea and adopt more and more chinese products. hope you can get away with this opion too.

To be honest, regarding quality, products from famous brands(such as Vailant, Nibe, Daikin) are better than that of other small brands, chinese products are cheaper, after-sale service is a big problem, but if you are a qualified engineer, nothing is difficult.