Author

Message

2008-05-28 16:23:51

Share your ideas, thoughts & comments

Dear R744.com Member,

here is your space to post any idea, topic proposal or question you might have about this forum or the website in general. Tell us what you like and where we still need to do some work.

Instant Hot water heat pumps

React to this Post

Hi,

I am interested in the Hitachi and Matsushita Panansonic Instant heat pumps.   I would like to use either of them on the output from a solar hot water heater to boost winter delivered water temperature.

At present the system uses an instantaneous gas unit.   I would like relative C.O.Ps for delivering water at 60, 45, 40 degrees C if input water temperatre us 20, 30,  etc

Are these units able to operate with input temperature higher than the expected delivered temperature.. i.e. if a tempering valve is installed inline to deliver 50degree constant by mixing in cold water.  This means that if tank water is above 45 (deired delivered temp) the instant unit will not turn on -- what is the standby electrical consumption of this unit.  The instant gas units use 7watts constant

Finally .. has anyone got a suggestion on how I will get either the Panasonic or Hitachi instant heat pump hot water unit into Australia -- I am building 200 eco village houses and would like to use this solution for winter boosting of rooftop solar hot water,.

RE: Share your ideas, thoughts & comments

React to this Post

Dear Matthew,

we have "transferred" your post to the "Export EcoCute" topic under "Heating" where it definitely fits. This message board is more to give us (R744.com Team) your feedback on the website and this forum.

RE: Share your ideas, thoughts & comments

React to this Post

I’m unclear as to why  the USA considers R134A with an AEL of 1000ppm to be safer than CO₂ with an AEL of 5000ppm for MAC applications? Please could someone enlighten me?

RE: Share your ideas, thoughts & comments

React to this Post

Where can I get information or reference material about using CO₂ in a secondary loop in a low temperature application (-20F)

RE: Share your ideas, thoughts & comments

React to this Post

Hei,

I am looking for information about oil-free compression of CO₂ for refrigeration prosesses. Within my student project my main focus is therefore based on centrifugal compressors.

Does anybody have experience or information about compression of CO₂ in centrifugal compressors?
Where wille be the problems by reaching the needed high pressure (~70bar) for CO₂ with a centrifugal compressor?

For example could it possible to modify the Danfoss Turbocor in a way that a usage of CO₂ could be possible?

RE: RE: Share your ideas, thoughts & comments

React to this Post

Hi Irven
I hope that you found what you are looking for. Otherwise you can find it under Johnson Controls pump stations

Best regards
Alex

RE: RE: Share your ideas, thoughts & comments

React to this Post

Johannes
I will not say that it is not possible because I don't know the specific pressure difference we are talking. As there are no valves in a turbo mashine, there is a limit to how much each step in the turbo can lift the pressure.

what is the suction pressure are we talking about?

Alex

OIL COLOUR

React to this Post

HI
I have just commissioned a sub critical co2 cascade system. The plant is ran by Bitzer comps and the oil is Bitzer BDE 85K. The oil in the compressor crankcases has a turned a light green colour. This is the first co2 plant that I have commissioned and I was wondering if this colouration of the oil was the norm.

RE: Share your ideas, thoughts & comments

React to this Post

It is not normal. Check and change filter driers ASAP.

RE: Share your ideas, thoughts & comments

React to this Post

I am an installation engineer who is installing co2 in well known supermarket.We are strength testing to 64 bar liquid side and have been asked to install schreiders in liquid lines on all cases after s.o.v.Is it right to have these fitted or should we be fitting valves with access ports?

RE: Share your ideas, thoughts & comments

React to this Post

Hi Anonymous,
Most cabinet manufacturers fit schreader valves after the shut off valves in the liquid line of the cabinets. They are specified under the BRA good practice guidelines and are neccesary when using Co2 to facilitate the correct pump down procedure. If you are unsure of the safety aspect of using schreaders at this pressure then a check on the valves specification should alleviate any worries.

Regards,
Mel.