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Heat Pumps - post here.

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    #1472
    Water John
    Registered Users Posts: 21,113 ✭✭✭✭Water John


    Zone the bedrooms, you have to, and any room with a second heat source, open plan the rest or with one master thermostat.


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    #1473
    NonPlussedNW
    Registered Users Posts: 6 ✭NonPlussedNW


    Thanks for all the responses. Lots to look at.

    John.G -Energy calculation. Going by the HP display, the system gets the buffer water up to temp and pauses once it gets to 38 or 39 degrees. It resumes once the water temperature falls back down to 33 degrees. Manifold out goes from 20 degrees room temp to 35 degrees when the pump starts. Manifold return temp doesn’t rise above initial 20 degrees at any point. Not sure that this is enough to go on to calculate a more reliable COP estimate, though.

    MENACE2010 – Airlocks. The flow meter is showing 1 litre/minute on the loop. Could there be an airlock and still be flow? I, perhaps wrongly, associate them with blockage.
    - Manifold actuators appear to be opening correctly, and showing flow as demanded by the relevant room stats.
    - I’ll get the installer to check the sensor accuracy, when he returns.
    - Water pressure valve shows around 1.5 Bar. The target indicator on the gauge has been turned to 2 Bar, but not sure if this was a deliberate setting by the installer or just how it came out of the box. The system seems to be holding at 1.5 bar and doesn’t appear to be losing pressure.
    - I’ve read the installation & planning manual. It gave me a better understanding of the setup, but left me not much the wiser about how I judge how well this installation is performing.
    - Uneven heating. I did wonder if poor pipe layout was the cause. Only the tiles over the first straight run of pipe show any significant heat increase, though, so it’s possibly the heat not penetrating far enough along the pipe run, rather than the layout.

    Water John – DHW temp is set for 50 degrees. There’s supposed to be a sterilizing boost, as MENACE2010 mentioned, but I haven’t noticed it kick in.
    - All heating loops are on stats, as far as I can see. HP and circulating pump don’t seem to run unless there is demand, though.

    Calahonda52 – Sub meter does sound like the best way to get definitive usage.
    - weather compensation is built in to the monoblock, but I’ll ask the installer to check.
    - (and Water John & MENACE2010) Too many zones. I was thinking it might be more efficient to merge some of the zones, but want to make sure the system as installed is working properly before getting creative.


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    #1474
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    WC is critical for HP installs as the lower the demand water temp the higher the COP.

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1475
    Water John
    Registered Users Posts: 21,113 ✭✭✭✭Water John


    Return temp sounds low IWT. Maybe the loops are over 100m. There should be a loop for about every 15 sqm, max 14 loops on one manifold. I think with the size of your house, you possibly should have two manifolds. That may be why the flow rate at 1l/min is low. Can you tell us how many loops you have?
    With everything on stats, any one stat will start the compressor, so you have more start/stops.


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    #1476
    John.G
    Registered Users Posts: 3,466 ✭✭✭John.G


    Re "easy" COP calculation, if you can tell me what the actual power consumption was for a complete cycle, ie from the time the compressor starts to stopping and measure the on time and the off times accurately then I can calculate a reasonably accurate COP for this period, obviously this only applies to the heating cycle so ensure that the hot water demand is satisfied before taking any readings....you are only talking ~ 0.25 to 0.5 kwh depending on the COP.


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    #1477
    NonPlussedNW
    Registered Users Posts: 6 ✭NonPlussedNW


    John.G wrote: »
    Re "easy" COP calculation, if you can tell me what the actual power consumption was for a complete cycle, ie from the time the compressor starts to stopping and measure the on time and the off times accurately then I can calculate a reasonably accurate COP for this period, obviously this only applies to the heating cycle so ensure that the hot water demand is satisfied before taking any readings....you are only talking ~ 0.25 to 0.5 kwh depending on the COP.

    Thanks for the offer to calculate the COP.

    Do you need the measurement of a single 6-7 minute On cycle, or of a full 1.5 hour run with multiple cycles that gets the room back up to temperature?


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    #1478
    John.G
    Registered Users Posts: 3,466 ✭✭✭John.G


    The cycle that I need is the both the 6/7 min ON time and the approx. 11 min off time, measure both times as accurately as possible and also the HP consumption during this time, it other words take the HP or/and ESB meter reading at the start of the ON period, compressor start, and take it again to when it stops. One complete cycle of ~ 17/18 minutes will suffice, for now.


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    #1479
    NonPlussedNW
    Registered Users Posts: 6 ✭NonPlussedNW


    John.G wrote: »
    The cycle that I need is the both the 6/7 min ON time and the approx. 11 min off time, measure both times as accurately as possible and also the HP consumption during this time, it other words take the HP or/and ESB meter reading at the start of the ON period, compressor start, and take it again to when it stops. One complete cycle of ~ 17/18 minutes will suffice, for now.

    Turns out there's no decimal places on my electricity meter so I can't get an accurate enough reading. I had a go anyway and the meter didn't move, so under 1 kwh, as you predicted.

    While I was doing this, it occurred that I'd still be relying on the unit's water temperature readings being accurate. If the HP unit's COP calculation is adrift it might be the sensors that are the cause. Might still be useful to compare the unit's total consumption reading with the meter to see if it seems close, so I might try that over a longer period.

    Thanks again for the offer, though.


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    #1480
    John.G
    Registered Users Posts: 3,466 ✭✭✭John.G


    Actually, I would think that the temperature readings would be quite accurate, in order to monitor it over a period of time you would have to count the number of cycles and you are hardly going to stand in front of it for a week!, the HP COP calculation is probably just summating these cycles and also the power consumed to arrive at a COP so it should be reasonably accurate but the COP should be ~ at least 3 and maybe a fair bit more when its only heating the water to 35C which is ideal really.

    Edit: Going on your original cycle times and assuming a compressor power of 3kw,I estimate that the COP was 2.2.


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    #1481
    Dardania
    Registered Users Posts: 3,612 ✭✭✭Dardania


    Kash wrote: »
    We have a 4 bedroom bungalow, built in the 70s. We are investigating installing a heat pump to replace/supplement our solid fuel stove. We had a SEAI registered assessor compete a technical assessment of the house, and he has given us a list of improvements - including installing UFH and replacing most of the windows and doors.

    He gave me a ballpark estimate of the improvements coming to €50-60k which we simply cannot afford.

    Is our dream of a warm house over?

    hi Kash - where was your technical advisor based, and would you recommend them?

    Or anyone else here registered - I am in South Dublin, and am looking to go A2W using the SEAI grant in my reasonably well insulated 1950s ex-Corpo house


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    #1482
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Dardania wrote: »
    hi Kash - where was your technical advisor based, and would you recommend them?

    Or anyone else here registered - I am in South Dublin, and am looking to go A2W using the SEAI grant in my reasonably well insulated 1950s ex-Corpo house

    Step one is airtightness must be up to scratch for a HP

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1483
    Dardania
    Registered Users Posts: 3,612 ✭✭✭Dardania


    Calahonda52 wrote: »
    Step one is airtightness must be up to scratch for a HP

    I reckon it's not bad albeit zero numbers to back up that assertion.

    I have EWI, modern windows & doors, sealed attic hatch, a balloon up the chimney, and using an Aereco DCV system for ventilation.

    How can I assess if it's up to scratch?


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    #1484
    John.G
    Registered Users Posts: 3,466 ✭✭✭John.G


    John.G wrote: »
    Actually, I would think that the temperature readings would be quite accurate, in order to monitor it over a period of time you would have to count the number of cycles and you are hardly going to stand in front of it for a week!, the HP COP calculation is probably just summating these cycles and also the power consumed to arrive at a COP so it should be reasonably accurate but the COP should be ~ at least 3 and maybe a fair bit more when its only heating the water to 35C which is ideal really.

    Is your compressor fixed speed or variable speed, if fixed speed I may still be able to give you a idea of COP.


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    #1485
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Dardania wrote: »
    I reckon it's not bad albeit zero numbers to back up that assertion.

    I have EWI, modern windows & doors, sealed attic hatch, a balloon up the chimney, and using an Aereco DCV system for ventilation.

    How can I assess if it's up to scratch?
    A blower door test really.
    Not the full passive house rig job, the more basic one

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1486
    sarah88
    Registered Users Posts: 502 ✭✭✭sarah88


    Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?


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    #1487
    ShanE90
    Registered Users Posts: 237 ✭✭ShanE90


    Cooling with a heat pump that is setup for space heating (Underfloor /rads) will produce poor cooling output as cold air falls to the floor you would need to be close to the floor to keep cool.

    Cooling the water in the system low enough to have any substantial cooling duty will cool the water below the dew point temperature of the surrounding air which will produce condensation...this rules out underfloor and radiators as they both will become wet.

    One option would be to use fan coils which are specifically designed to collect condensation formed during cooling... this should be setup as an independent zone as all the pipework needs to be insulated with armaflex which has a vapour barrier, fan coils can also be used for heating.

    Some manufacturers have fan assisted rads that can be used for cooling as they have condensate trays also.

    Alternatively a split ac system which would be totally independent of the heatpump could be used it will work better and be more for for purpose


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    #1488
    sarah88
    Registered Users Posts: 502 ✭✭✭sarah88


    ShanE90 wrote: »
    Cooling with a heat pump that is setup for space heating (Underfloor /rads) will produce poor cooling output as cold air falls to the floor you would need to be close to the floor to keep cool.

    Cooling the water in the system low enough to have any substantial cooling duty will cool the water below the dew point temperature of the surrounding air which will produce condensation...this rules out underfloor and radiators as they both will become wet.

    One option would be to use fan coils which are specifically designed to collect condensation formed during cooling... this should be setup as an independent zone as all the pipework needs to be insulated with armaflex which has a vapour barrier, fan coils can also be used for heating.

    Some manufacturers have fan assisted rads that can be used for cooling as they have condensate trays also.

    Alternatively a split ac system which would be totally independent of the heatpump could be used it will work better and be more for for purpose

    Thanks a mill for the detailed reply, its really helpful.


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    #1489
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    sarah88 wrote: »
    Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?
    as above, wont work with A2W, will work with A2A

    An alternative, if you have MVHR is to put a cooling coil in it, however it's a bit complicated as to ensure you just don't drive up relative humidity, the air has to be chilled down to get at least some of the moisture to drop out.
    http://www.dpcalc.org/

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1490
    Mr Q
    Registered Users Posts: 984 ✭✭✭Mr Q


    sarah88 wrote: »
    Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

    I have my A2W setup to do this with the underfloor system. It won't cool the house in the same way A2A would but it is definitely noticeable on the warmer days.


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    #1491
    ercork
    Registered Users Posts: 177 ✭✭ercork


    sarah88 wrote: »
    Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

    I got an A2A installed a few years ago for heating. I never took too much notice of the fact that it had a cooling mode. The summer before last was particularly warm and I switched it on for a while. It worked great - one night I even slept on my couch in the living room where the A2A is located because the bedroom was so warm!
    I only ended up using it for a week or so so I don't really know what the running costs were.


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    #1492
    Shefwedfan
    Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    ercork wrote: »
    I got an A2A installed a few years ago for heating. I never took too much notice of the fact that it had a cooling mode. The summer before last was particularly warm and I switched it on for a while. It worked great - one night I even slept on my couch in the living room where the A2A is located because the bedroom was so warm!
    I only ended up using it for a week or so so I don't really know what the running costs were.

    How is the A2A for heating compared to A2 W? Do people know?


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    #1493
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Shefwedfan wrote: »
    How is the A2A for heating compared to A2 W? Do people know?
    The main issue with A2A is that you really cannot take advantage of night rate power to either heat up the slab or better, heat a thermal store.
    A2A is much faster response so I have just specified one in a community facility to act a rapid response boost on top of an A2W rad system to heat the hall for the older generation

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1494
    Count Mondego
    Registered Users Posts: 963 ✭✭✭Count Mondego


    sarah88 wrote: »
    Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

    I have a Geothermal HP that's integrated with the HRV system and cools the air. Also the Nilan Geo Heatpumps integrate both HP and HRV in one unit and can do the same. Can drop the air temperature up to 10 degrees


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    #1495
    Dardania
    Registered Users Posts: 3,612 ✭✭✭Dardania


    Calahonda52 wrote: »
    A blower door test really.
    Not the full passive house rig job, the more basic one

    So, a very nice chap did the technical assessment for us, and our projected heat loss indicator will be 1.79W/K m2 - so meeting the threshold needed to avail of the SEAI grant.

    Does anyone have any recommendations for heat pump suppliers & installers, active in the south dublin area? I want to go A2W, and ideally figure out some solution for DHW at the same time


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    #1496
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Dardania wrote: »
    So, a very nice chap did the technical assessment for us, and our projected heat loss indicator will be 1.79W/K m2 - so meeting the threshold needed to avail of the SEAI grant.

    Does anyone have any recommendations for heat pump suppliers & installers, active in the south dublin area? I want to go A2W, and ideally figure out some solution for DHW at the same time

    What stage is the design at?

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1497
    Dardania
    Registered Users Posts: 3,612 ✭✭✭Dardania


    Calahonda52 wrote: »
    What stage is the design at?

    I'm living in the house - this would be retrofit. Call it "scoping" stage!


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    #1498
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Dardania wrote: »
    I'm living in the house - this would be retrofit. Call it "scoping" stage!

    Dis you get an SR 50 calc done to size the rads, I have a guy in Tullamore who might do it but the design needs to be right first.

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1499
    JonMac
    Registered Users Posts: 467 ✭✭JonMac


    I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
    I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
    My gas boiler has been set at 13kW and that worked very well.


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    #1500
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    JonMac wrote: »
    I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
    I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
    My gas boiler has been set at 13kW and that worked very well.

    What math did you do, give an example pls of one external wall?

    “I can’t pay my staff or mortgage with instagram likes”.



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    #1501
    Shefwedfan
    Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    JonMac wrote: »
    I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
    I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
    My gas boiler has been set at 13kW and that worked very well.


    How do you do a technical assessment and then not recommend the heat pump? bit of a get out of jail card that one isnt it


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