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Author Topic: Proven 6kw Turbine / SMA Windy boy Inverter Advice sought...  (Read 5860 times)
donegal
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« Reply #30 on: April 19, 2019, 09:34:36 AM »

What does a buffer tank look like ?


Most systems have a water cyliner, say about 150L either between the GSHP and UFH or on the return leg of the UFH,  this is seperate from your hot water cyliner.  Its there to
prevent short cycling (constant on/off of the GSHP) and possibly give a 'boost' when heating is needed, as theres a store of water at say 30 degrees ready when required. The larger volume of water in the system limits the stop / start .

If there is no buffer then this could be the problem / solution,  as the soft start may last 10-20 years if the GSHP was only turning on 6 times per day rather than say 20 times.

Ive seen dimplex comercial installs that dont have a buffer, so it may be possible to adjust flow rates etc to have the system work without a buffer, but most systems
have a buffer.

Id be wary of refigeration engineers and heatpumps,  theres a risk that all they can service is the compressor, there ok for regassing but might not be aware of how the system should run.

PDF who posts on here has very good knowledge of GSHP, from what ive seen of his posts, he may be able to advise further.

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marshman
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« Reply #31 on: April 19, 2019, 11:51:15 AM »

Here is a pic of my system installed in Dec 2015, so has nearly completed 4 heating "seasons". so far, hoping I'm not speaking too soon, 0 maintenance.

I have labelled the DHW tank and the small buffer tank. My heatpump is the non "inverter" type so the compressor is either on or off. In "normal" average conditions it is on once every hour and a half or so and runs for approx 20 mins. It does all the heating and DHW in the cold months. Over holiday periods when the kids decend with their partners there are up to 10 people in the house all using showers etc and there is never a shortage of hotwater, the large tank helps. Like others I can only think that the soft start controllers are failing due to the number of starts the pumps are doing. There are no buffer or DHW tanks visible in your picture just expansion vessels (required for unvented systems). Do you have a DHW storage tank?

Again. as previously mentioned, refridgeration engineers may be able to fix the heatpump but are unlikely to understand the whole system and ensure it is set up and running correctly. With my system it took nearly the whole of the first heating season to get everything adjusted correctly so that the house was always a comfortable temperature and the system ran as economically as possible. I know it hasn't been a cold winter but consumption this year (year 4) is over 30% less than in the first year - and the first year did not start until mid December!

I think DonL mentioned in another thread that heat pumps work best on long runtimes at low temperatures, mine system runs 24/7 in the heating season, no timers,  and is so economical plus the house is always warm. In my opinion the problems start when people try to operate them like a gas or oil boiler system.

Roger


* system.jpg (261.36 KB, 1466x1102 - viewed 578 times.)
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3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
donegal
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« Reply #32 on: April 19, 2019, 01:22:49 PM »

Great photo Marshman, i envious of the space you have.  my system was a last minute addition to a new build in 2003, so everything was shoehorned in, it a **** to work on.

Im still adjusting my system /  timimg / flo temps after 16 years   Grin,   the comfort was always there but each adjustment gives a bit more economy, adding solar , turbine etc.

I currently lift the room temperatures at night by a degree over whats required , this seems to give a longer run time at night on night rate electricity and reduce running
during the day to an hour or two at most, if at all. it seems to work for me.
I also run the bedroom areas for two hours at the start of the night when the flow temperatures are low and then concentrate on the living accomodation for the rest of the night (my house is upside down, so that may not work for all)

The comment on not treating it like a boiler, is soo true.  the systems appear to be designed with fine margins, Slight changes to flow temperatures / times make a difference, but it may be a few days before you see the final results. If it works like an oil boiler then its wrongly sized.

I understand the constant start ups are also very sore on the compressor and i was also advised by an electrical engineer that a soft start is failing slowly with every use, thats the nature of them (could have been due to arcing/pitting).  Can anyone confirm that or correct it ?
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rogeriko
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« Reply #33 on: April 19, 2019, 06:55:03 PM »

jonsamcor if you had a buffer tank you could heat it with the power from the proven turbine and you wouldnt even need a heat pump at all.
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jonsamcor
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« Reply #34 on: April 20, 2019, 09:01:49 AM »

No buffer tank .....
Just a couple of DHW tanks in the house ....a problem I think I have is when the GSHP goes down the water heated by the vacuum tubes gets taken into the UFH ....I think ....just because when pump has been down and itís a great day for solar  I donít have hot water.
The engineeer was trained by Dimplex re servicing their pumps so knew what he was at
The installer for the new one coming Ecoforest is local and has impressed me with his knowledge to date ....
There is no soft start in their pump ..... we shall see .... but will ask the question re a buffer tank
Again thanks for the advice
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Rural Co. Down, Proven 6kw Turbine, GSHP, Thermomax Tubes....and Total lack of technical or useful knowledge
rogeriko
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« Reply #35 on: April 20, 2019, 09:36:30 AM »

You should have a buffer tank with a couple of immersions in the bottom then you could divert the electric from the turbine to the immersions instead of exporting it. All our heatpump installs have a buffer tank.
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donegal
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« Reply #36 on: April 20, 2019, 10:53:43 AM »

No buffer tank .....
Just a couple of DHW tanks in the house ....a problem I think I have is when the GSHP goes down the water heated by the vacuum tubes gets taken into the UFH ....I think ....just because when pump has been down and itís a great day for solar  I donít have hot water.
The engineeer was trained by Dimplex re servicing their pumps so knew what he was at
The installer for the new one coming Ecoforest is local and has impressed me with his knowledge to date ....
There is no soft start in their pump ..... we shall see .... but will ask the question re a buffer tank
Again thanks for the advice


I had a look at the Ecoforest literature,  they say they dont need a Buffer tank due to the inverter technology, so maybe Dimplex were the same.  Either way
the constant starts point to another problem in the system.
The commercial dimplex install i mentioned had similar initial problems with Domestic hot water bleeding into the UFH due to a faulty one way valve in the system pipework.
Just make sure the new installer is aware of the problems and get a schematic of thier proposals. Theres a risk they will simply replace the heatpump and blame
any probelms on the existing system, they really need to take responsibility for the design of the existing system.

The Dimplex heatpump in that install gave no problems and hasnt been serviced for 7 years
« Last Edit: April 20, 2019, 11:22:33 AM by donegal » Logged
linesrg
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« Reply #37 on: April 20, 2019, 11:06:04 AM »

No buffer tank .....
Just a couple of DHW tanks in the house ....a problem I think I have is when the GSHP goes down the water heated by the vacuum tubes gets taken into the UFH ....I think ....just because when pump has been down and itís a great day for solar  I donít have hot water.
The engineeer was trained by Dimplex re servicing their pumps so knew what he was at
The installer for the new one coming Ecoforest is local and has impressed me with his knowledge to date ....
There is no soft start in their pump ..... we shall see .... but will ask the question re a buffer tank
Again thanks for the advice
jonsamcor,

You say there is no soft start in the Ecoforest heat pump, surely if it is inverter driven and variable then it must have a soft start almost by definition?

Regards

Richard
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1.28kW on a Lorentz ETATRACK1000 + 1.44kW/ SB3000TL-21 (FIT), 1.28kW/ SB1700 (ROO/FIT). CTC GSi12 heat pump/Ecosol/Flowbox 8010e/Gledhill ASL0085 EHS/3off Navitron 4720AL Solar ET & Immersun T1060/T1070/T1090. 3.375kW/ SMA SB3600TL-21 and a Sunny Island 4.4M-12 c/w 15.2kWh battery and a Renault Zoe.
donegal
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« Reply #38 on: April 20, 2019, 01:56:35 PM »

Thinking back, i has the same problem with my UFH using the DWH and solved it by putting a motorised valve on the DHW supply, which was activated by the hot water timer, so there could be no unintended flow through the HW Cylinder. This wasnt much of a problem initailly as i didnt have solar. it became noticable when i went to bed with a tank of 60 deg HW and woke up to a tank of 35 deg HW. Your installer should be addressing this without being asked.

It sounds to me like you may not be too far from a good system, but you need more facts on what the new install includes. Modifying the existing system
to suit the requirements of the new GSHP is something I would insist on as part of the price. i know im cynical, i wasnt always !.

I just envisage changes/upgrades that you will be charged for if problems arise, Hopefully not.

Appologies to the Turbine people for hijacking this thread, but it appears that the turbine problems may be easier to sort if the GSHP is running
correctly (and with a soft start ?)

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rogeriko
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« Reply #39 on: April 20, 2019, 02:21:57 PM »

On an Eco-Forest heat pump the inverter drive IS the soft start. The compressor starts very slowly and builds up to full power (if required) over about a minute. They have seperate outlets for DHW and heating with a common return. You set the temperatures on the control panel and the unit does the switching between DHW and heating. I hope the installers know how to replumb the system!!
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jonsamcor
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« Reply #40 on: April 21, 2019, 07:34:49 PM »

Correction ....I think I do have a buffer tank ....
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Rural Co. Down, Proven 6kw Turbine, GSHP, Thermomax Tubes....and Total lack of technical or useful knowledge
jonsamcor
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« Reply #41 on: April 21, 2019, 07:53:10 PM »





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Rural Co. Down, Proven 6kw Turbine, GSHP, Thermomax Tubes....and Total lack of technical or useful knowledge
jonsamcor
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« Reply #42 on: April 21, 2019, 07:59:57 PM »

The pump house adjoins the garage, there is a room above the garage and whilst being built I saw that there was no heat to it should asked for a couple of rads to be put in take the chill off in bad days.....

So I guess that they didnít think there was sufficient room in ďpump houseĒ for buffer and they put it next door in the garage ...... I had just assumed that it was stuck in there because I had asked for heat above the garage whilst they were well on in construction and it was a bolt on ......
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Rural Co. Down, Proven 6kw Turbine, GSHP, Thermomax Tubes....and Total lack of technical or useful knowledge
jonsamcor
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« Reply #43 on: April 21, 2019, 08:07:33 PM »

I will put the issues re solar water etc to the new guy.....but I will get you lot to mark his homework......
I am pretty certain now that the cut off /humming is a result of the soft start being removed ....
I have witnessed it a few times in the garage today ......
Hopefully the new pump will cut that out .....
Today was the most beautiful Easter Sunday I can remember....... just wish I had a load of PV panels on my south facing garage roof .....
Again thank you 🙏 for the help
9-5 Iím a Solicitor (donít hate me) if I can help any of you I will ask away ....
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Rural Co. Down, Proven 6kw Turbine, GSHP, Thermomax Tubes....and Total lack of technical or useful knowledge
oliver90owner
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« Reply #44 on: April 21, 2019, 11:26:54 PM »

This humming.  When does it occur? Does the motor actually start and operate normally?  I ask because any heat pump with hard start needs to have the compressor off-load at start up. 

A domestic fridge or freezer has an overload cut-out for cases where people turn the compressor off and on in too-short a period.  The motor will then try again, to start, after the overload has cooled off.
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