air source heat pump:how to make water reach 80℃?

[billliu2010]

In air source heat pump system, how to make water temperature reach 80℃? Only choose different refrigerant and compressor ? How to evaluate COP, does it relative to rated hot water output volume? For example:
heating capacity: 34.5KW(120000btu)
COP:2.7
Rate hot water output volume: 560Liter/hour
rated power input: 12.8kw
rated current input: 25.2A
max power input: 17.3kw
max current input:34.1a

scroll compresor, R134a,

How about the COP:2.7, how about the rated hot water output volume:560l/h.low or high?

Thanks for your kindly suggestion.Have a good day.

[nike123]

Easy.;) Fit desuperheater before condenser!

[mad fridgie]

As easy as that, "I wish"

You can but what ever set of numbers you want into a program and get the answers you want. So that being the case yes numbers looks OK.

[nike123]

As easy as that, "I wish"


:D I dont see anwhere water inlet temperature, so theoretically, it is just that easy.:D

[desA]

Have fun on the condenser 'pinch'. :D

Will be useful to have a few spare compressors on hand.

[goshen]

Have fun on the condenser 'pinch'. :D

Will be useful to have a few spare compressors on hand.
Hi
A desuperheater will get u up to 65c max ,and from personal experiance it works very well!

[nevgee]

Is it really so easy?

Surely you need to consider the gas characteristics?:D
You need to look at a Ph diagram and see there are different dicharge temps for each and every refrigerant. A superheater wont give you the 80C you need if the refrigerant can't deliver the temperature at the desired pressure..... so is this still "simple" ;)

[mad fridgie]

Is it really so easy?

Surely you need to consider the gas characteristics?:D
You need to look at a Ph diagram and see there are different dicharge temps for each and every refrigerant. A superheater wont give you the 80C you need if the refrigerant can't deliver the temperature at the desired pressure..... so is this still "simple" ;)
On a simulation program, when "you input" perfect numbers, it is that easy, BUT, when in refrigeration is it always perfect? So yes is simple in theory (so is sending a man to the moon), but I can say in practice is not.

[Tesla]

For a start forget about R134a. Look at R22 (but that's being phased out) so check out CO2. Look for a compressor with 2 stage compound, I saw a rotary as such yesturday but a scroll would be better. Operate in the transcritical region and be careful of the pinch like mad fridgie said.
As for the COP measure it = output (heat added to water) divided by input (kWs electrical power)

[nevgee]

I think scrolls have a condensing limit with R134A about 70C / 21barg discharge temp ~ 82C will this be enough? ... will a scroll run happily at this limit and will it's service life be compromised?

... is this still "simple" :D

[mad fridgie]

As a manufacture of heat pumps who produce water just short of 90C with eCOPs of upto 10, I can say in theory it is that easy!, in practice is certainly not. At these temps very small changes can make very big. differences in performance and reliabilty.
there are number of methods of achieving these temps, I personally think CO2 heat pumps are overrated at its current price tag.

[billliu2010]

First,thanks for all the comments and suggestions above. You're welcome to continue ......

sorry, the inlet water temperature is 27℃, ambient tem(dry ball/wet ball)7℃/6℃. Inlet and outlet water tem in condenser: 40℃/60℃, the max tep. can reach 80℃. How about the inlet and outlet water tem. in condenser? How about the COP:2.7, how about the rated hot water output volume:560l/h.low or high?
Thanks for your kindly suggestion.Have a good day.

[mad fridgie]

First,thanks for all the comments and suggestions above. You're welcome to continue ......

sorry, the inlet water temperature is 27℃, ambient tem(dry ball/wet ball)7℃/6℃. Inlet and outlet water tem in condenser: 40℃/60℃, the max tep. can reach 80℃. How about the inlet and outlet water tem. in condenser? How about the COP:2.7, how about the rated hot water output volume:560l/h.low or high?
Thanks for your kindly suggestion.Have a good day.
New figures, also "possible"!!!!
Big difference between possible and likely.

[billliu2010]

New figures, also "possible"!!!!
Big difference between possible and likely.

Pls kindly suggest on how to make possible to likely.

[desA]

^ Why don't you hire MF to design your next range of heat-pumps?

[billliu2010]

^ Why don't you hire MF to design your next range of heat-pumps?

1.This forum is for exchange opinions freely, openly, non-profitable ,if i pay MF ,it will against the purpose of this forum, I think.
2.I cann't, I am poor:D

[mad fridgie]

Thanks DesA, It would be nice to have a fully paid trip to China!
Billiu2010, you are sort of correct this forum is free exchange of ideas, but not when it come to interlectual property.
Your first questions were acceptable and we have given answers.
When it comes to how to, you need to research, test, blow-up equipment, gain experience and basically spend a lot of money.
If you want to use the forum to full potential, you need to ask very specific questions, then you can get the answers from indvidual specialists.
If you developing in this market, then you will be poor, just like the rest of us :)

[desA]

If you developing in this market, then you will be poor, just like the rest of us :)

Amen to that. :D

[Gary]

Generally people who want a free exchange bring nothing to the table.

[billliu2010]

Thanks for all the comments related with this suject . I agree with your opinions. If my question come to interlectual property, I would like to exchange for the evalue it cost. Of course i would like to invite MF to china if he can help me with IP issues.
But my question is ask how about the evalue of cop and outlet water volume , inlet and outlet water tem from condensor, do these related with IP . I'm puzzled..........

[mad fridgie]

(L/S * 4.187 * (To-Ti))= Heat output
KWout/KWin = COP
No Not IP
Done!

[desA]

No IP to China, sorry. :(

[billliu2010]

No IP to China, sorry. :(


We have our own, so no need.Maybe we have more than some small place.......


Many thanks to MF , you're a good person.

[Tesla]

Hi billliu2010
Not sure where you got your numbers from. On a quick calc (roughly) from water 20K and flow of 0.155l/s I get 13kW. If you measure A and V then multiply A, V and power factor you will have you power input in kW's. So divide the output kW's by input kW's.
For the flow rate 560l/h is the same for a shower. You can search this forum for all the data you need such as COP, formulas, caclulations and other technical matters.

[desA]

We have our own, so no need.Maybe we have more than some small place.......


It would perhaps be a start if you placed some of your ideas, proposals, calculations, sketches, or solutions up on the board for us to comment on.

This will be both useful for you as well as for the forum members. In this way, we all get to learn something new. Then it becomes a win-win situation instead of members giving you solutions on a plate. :)

[dougheret0]

In air source heat pump system, how to make water temperature reach 80℃? Only choose different refrigerant and compressor ? How to evaluate COP, does it relative to rated hot water output volume? For example:
heating capacity: 34.5KW(120000btu)
COP:2.7
Rate hot water output volume: 560Liter/hour
rated power input: 12.8kw
rated current input: 25.2A
max power input: 17.3kw
max current input:34.1a

scroll compresor, R134a,

How about the COP:2.7, how about the rated hot water output volume:560l/h.low or high?

Thanks for your kindly suggestion.Have a good day.

The rating is for a starting temperature of 27 C. Running the numbers

one liter of water weighs 1 kg
Q = kg/hr*cp*∆T
cp = 1 cal/gm/˚C or 1000 cal/kg/˚C
Q = 560*1000*(80-27)=29660000 cal/hr

Q = 34.5 KW

So if your entering water is cooler than 27 C, or if the heat pump condenser air is cooler than design, you will not get 80 C water out.

[cadillackid]

I still hold the conclusion that with ambient temp of 6 or 7 degrees C you are better off "preheating" the water with the heat pump and then using Gas or electric fired Boiler to finish the Job.
-Christopher

[billliu2010]

It would perhaps be a start if you placed some of your ideas, proposals, calculations, sketches, or solutions up on the board for us to comment on.

This will be both useful for you as well as for the forum members. In this way, we all get to learn something new. Then it becomes a win-win situation instead of members giving you solutions on a plate. :)

Yes, it's my start here and it's the good atmosphere here that let me decide to be a member ,without my info. where is the hot discuss, where is something new , not a win-win? Don't so be practical.

Then, what's the meaning of " No IP to China",does it
relative with my question? pls kindly suggest,thanks.

[desA]

Then, what's the meaning of " No IP to China",does it
relative with my question? pls kindly suggest,thanks.

It's very simple. What I've noticed during my time on RE, is that a number of probing questions seem to come from China, but very little, if any, information flows back to the forum for others to digest. It seems like a one-way flow. This is basically unfair.

My personal view is not to send any IP to China. You will find that this view is also shared by a number of developers. There are numerous stories of blatant IP theft in China, & I have no interest in making you, or your company wealthy off free IP. If you are prepared to pay the going market rate, then I'm sure that some parties will be prepared to discuss with you.

Anyway, apologies for interrupting your thread with my personal view. Put up your calculations & I'm sure you will get some interesting answers. :)

[billliu2010]

As a manufacture of heat pumps who produce water just short of 90C with eCOPs of upto 10, I can say in theory it is that easy!, in practice is certainly not. At these temps very small changes can make very big. differences in performance and reliabilty.
there are number of methods of achieving these temps, I personally think CO2 heat pumps are overrated at its current price tag.

Can make it with the above mentioned data after confirming with our related engineer.....
As for CO2 heat pump can make it also and it's mature in Japan, and then in Europe,but it's cann't be popular at present because of it's high price. Just like what you said.Thanks!

[billliu2010]

I still hold the conclusion that with ambient temp of 6 or 7 degrees C you are better off "preheating" the water with the heat pump and then using Gas or electric fired Boiler to finish the Job.
-Christopher


Sorry, After confirming I find my data provide by my engineer is not corret. The ambient tep. (dry ball/wet ball) should be 24/19c . So it's ok, I think, thanks.

[billliu2010]

The rating is for a starting temperature of 27 C. Running the numbers

one liter of water weighs 1 kg
Q = kg/hr*cp*∆T
cp = 1 cal/gm/˚C or 1000 cal/kg/˚C
Q = 560*1000*(80-27)=29660000 cal/hr

Q = 34.5 KW

So if your entering water is cooler than 27 C, or if the heat pump condenser air is cooler than design, you will not get 80 C water out.

Got it,many thanks for your clear answer.

[billliu2010]

It's very simple. What I've noticed during my time on RE, is that a number of probing questions seem to come from China, but very little, if any, information flows back to the forum for others to digest. It seems like a one-way flow. This is basically unfair.

My personal view is not to send any IP to China. You will find that this view is also shared by a number of developers. There are numerous stories of blatant IP theft in China, & I have no interest in making you, or your company wealthy off free IP. If you are prepared to pay the going market rate, then I'm sure that some parties will be prepared to discuss with you.

Anyway, apologies for interrupting your thread with my personal view. Put up your calculations & I'm sure you will get some interesting answers. :)

As for one-way flow, I has the same idea as you, I cann't stop others from doing this,but I'm trying not to .
As for the IP issue, I don't want to comment much, I only say" part doesn't stand for all" , If you insist on your prejudice ,this forum will lose something in a certain degree. We are for technical free discussion (excluding IP)but not politics, we should always try to find good things and try to prevent bad things without any prejudice. This is my private opinion .

Anyway,thanks for your time of telling me why. No need apologies because we should have a free and friendly atmosphere here.

Thanks for all the friends comment here.

[Magoo]

DesA and Mad fridge, stand up and take a bow.
magoo.

[billliu2010]

Hi billliu2010
Not sure where you got your numbers from. On a quick calc (roughly) from water 20K and flow of 0.155l/s I get 13kW. If you measure A and V then multiply A, V and power factor you will have you power input in kW's. So divide the output kW's by input kW's.
For the flow rate 560l/h is the same for a shower. You can search this forum for all the data you need such as COP, formulas, caclulations and other technical matters.

Thanks for your answer and suggestion, in our country, usual shower outlet volume is 8-10L/min,I just want to confirm it in other countries,becasue one of customer said it was lower . Now I understand.Thanks.

[desA]

Amazed at how the OP moves from being a poor individual interested in heat-pumps, to one with customers and engineers.

:confused:

If you want IP, arrange a technology transfer deal for your company, & pay for it. Someone may want to assist you, but certainly not me.

[Tesla]

Hi billliu2010
Yes 8 - 10 l/s is what is used in ausie and nz.
No disrespect to other members but in my mind patents and IP are not really fair, in saying that I would be pissed if someone else patented one of my ideas and I do realise that some need to make a living and invest on R+D, requiring a return. Considering some inventors have been knocked off for thier ideas.
Search my threads and I'm sure you will find most if not all the info you need.

[Gary]

No disrespect to other members but in my mind patents and IP are not really fair, in saying that I would be pissed if someone else patented one of my ideas and I do realise that some need to make a living and invest on R+D, requiring a return. Considering some inventors have been knocked off for thier ideas.

Historically, almost all inventors are knocked off for thier ideas. Patents are at best ineffective and at worst counter-productive. When you apply for the patent, you tell the world how you did it.

There is no effective way to reward the people who most benefit mankind. Its a wonder that technology keeps moving forward. The only real protection is secrecy... and you will need to reveal those secrets to those who develop/build/market your ideas. Who can you trust?

When you build the better mousetrap, the IP thieves beat a path to your door.

[desA]

Patents are useful in countries where the IP can be strictly enforced.

IP thieves will always be what they are - thieves. This is why very few developed nations will send new technology to Asia.

[billliu2010]

Patents are useful in countries where the IP can be strictly enforced.

IP thieves will always be what they are - thieves. This is why very few developed nations will send new technology to Asia.

Then where are you from? how about IP in your country?? Pls kindly suggest!

IP should be protected within a certain peroid,if cannot, the society will has no progress, the point is how to prevent properly without exaggerated /distorted.

[desA]

Develop your own IP at cost, then you too can protect it. :D

As Tesla stated, do a search on RE, there will be a lot of information (the free sort) to help you on your way.

As I also stated, do take care of the 'condenser pinch'. Pushing temp over 80'C is possible & some of us have developed technology to do exactly this, and higher actually. We will however, protect that knowhow, in order for our families to eat.

[billliu2010]

Amazed at how the OP moves from being a poor individual interested in heat-pumps, to one with customers and engineers.

:confused:

If you want IP, arrange a technology transfer deal for your company, & pay for it. Someone may want to assist you, but certainly not me.


If my quetion is related with IP wittingly or unwittingly,I won't force you to answer, I cann't,you can choose not to answer, if you are enough friendly ,you can tell me my question is related with IP.
I have said if I need IP,I will pay for it ,of course not you. NOT always exagerate such simple questions, pls kindly confirm what is IP, what isn't IP, not to say everything is IP,or you cann't speak here.

My word is not only to you, to all the persons who always want to exagerate something or with discrimination.

Here should be a place to discuss things about heat pump freely and friendly, not alway to talk so much nonsense things,or what's the meaning of establishing this forum?

Thanks for all the comments on this issue!!

[desA]

Hi billliu2010,

If you & your company is serious about purchasing IP, which you now seem to be, then MF has made you an offer to assist. Talk with him, using the private-mail feature on the RE board. He's a nice guy & will get you sorted out, I'm sure.

All the best & apologies for being a little hard on you. :)

[cadillackid]

in a design phase if something is regarded as a design secret or IP.. why even post about it on an open forum?

I work on and design a lot of things.. some of the projects are fun, some are proof of concept, some are truly design.. I only post on an open internet forum those projects and ideas which i feel may be helpful to others without compromising my possible future business ventures....

sure, like anyone else I enjoy and like to entertain others' ideas, however I dont Expect just because I post here that someone is going to come along and do the job for me for free.... so I expect on a forum vague ideas and responses... often those point me in a direction that is a huge help..

-Christopher

[billliu2010]

different jobs ,different requirement, different opinions! I'm sales ,only concept, no IP needed, so pls don't worry, I won't seize your bowl. :off topic:

[desA]

The story-line morphs yet again. :D

[mad fridgie]

I thought I would clear up the IP
The vapour compression refrigeration cycle has been around over 100 years, it has been tweeked, different compressor, elctronics, refrigerants, but all said and done it has not changed, you can not beat the laws of physics.
So you need six parts, compressor, evap, cond, expansion device, refrigerant and some thing to drive the system. Understand this then you are on your way.
IP or could be said Knowledge, this is gained through experience, some information we share, other information we do not. The NOT information is normally info that may effect our businesses, thus our families. Of course this information can always be purchased, this is the case when ever you pay for something that you can not do yourself.
In this field it is normally the concept/application that is classed as IP more than specifics, very few of use can say that we have built a whole system from raw materials (I have not), most still requirer major components from others, example compressor (only a limited number of manufactures world wide)

[desA]

IP, or specialised knowhow.

Every professional uses their specialised knowhow to earn a living - lawyers, doctors etc. Engineers are no different.

Raising water temp reliably & safely to 80'C does require a certain amount of specialised knowhow - this knowhow comes at a cost in terms of design, experimentation & analysis expenses. The specialist engineer has a right to both protect this knowhow, & to charge for it, in order to recover their financial outlay.

What many specialists do, however, is to combined their specific expertise into co-operative ventures, where information is inter-traded, until a certain final product is ready for market release. The profits from these products are then shared amongst the co-operative partners.

Much of the information on RE is of a very general nature & can be freely shared. The ethical questions arise when specialist information is requested. If certain members are prepared to provide this information at no cost, then that is their right. We all have different views on where we draw the line.

[billliu2010]

Every IP have protection peroid,this is,maybe today it's is IP,tomorrow is know-how/knowledge, so during the protection peroid, illegal usage is forbidden ........

[Pete Hutson]

First,thanks for all the comments and suggestions above. You're welcome to continue ......

sorry, the inlet water temperature is 27℃, ambient tem(dry ball/wet ball)7℃/6℃. Inlet and outlet water tem in condenser: 40℃/60℃, the max tep. can reach 80℃. How about the inlet and outlet water tem. in condenser? How about the COP:2.7, how about the rated hot water output volume:560l/h.low or high?
Thanks for your kindly suggestion.Have a good day.
Cascade second stage is the only reliable way to reach these temperatures. R410A over R134A seems to be the answer.

[mad fridgie]

Cascade second stage is the only reliable way to reach these temperatures. R410A over R134A seems to be the answer.This is one method, but you do not need to cascade R410a, I have system prototypes running, on DHW (double barrier heat exchangers) that produce water well over 80C. I am able to store 50% more energy in a cylinder (if required, but normally not) than present systems available in NZ, the system is able to work in bigger ambient ranges, and has greater COPs than any system presently on the market. All this makes the unit much more reliable, than any system on the market.
The SFT principle (which is Patented) has been tested R410a, R22, R134a, R407C, it will work on any sub critical refrigerant. In each case with a general reducion in power of 30% for the same amount of stored energy produced. They are mechanical principles, not electrical savings (which would further improve COP, ie DC motors)