June 6, 20242 yr Hi Forum, Not sure if this has been asked before, but we just built our house in Centurion. The developer installed a 3.6kw ITS heat pump to a 200l geyser. Like all developers do, once the house has been built, they aren't much help with how to run things. I have a solar system installed, sunsynk 8kw with 2 5.12 batteries. I currently use the heat pump on a timer 5am - 7am (not as hot water as we want) and then 12pm - 15h30pm (hot water is good for an evening shower) - with this set up, I am pulling about 1-2kws from the grid but, I still would like a hot shower in the morning. My problem is, it's winter and the air is much colder, which I am assuming as to why the morning shower is not so hot. I then reached out to the developer today, who says keep the heat pump on constantly because it damages your pipes in winter (compression and expansion with the temperatures) and by running a timer I would use the same amount of electricity than from turning the HP off and on with a timer. The HP pulls around 860-960w, which doesn't sound too bad, but I did try that today and my batteries are already down to 66% at 8pm. (before this recommendation, I would reach 60% just before sunrise and then the grid and PV would run the HP in the am.) I also learnt today that the HP heats about 65l/h. That would mean I would need a good 3 to 3.5 hours in the morning for the water to reach 50deg. I guess what I am asking for in the forum is specifically: How on earth does one get the best benefit from this HP? Does one leave it on the whole day with the geyser (mine is currently off and on non-essentials)? Does one use a timer? If using a timer, how does one set it on the Smart Life App? When turning it off is there a target temperature it should reach? How long should I run it for if timed? Does using a timer damage the HP and the piping in the long run? (We did hear a pop in the ceiling the other night and have seen a slight leak - could it be from this off/on situation?) Any help would do here - I am wrecking my brain trying to figure out the best usage of the HP.
June 6, 20242 yr 6 minutes ago, Ras_al_Ghul said: Hi Forum, Not sure if this has been asked before, but we just built our house in Centurion. The developer installed a 3.6kw ITS heat pump to a 200l geyser. Like all developers do, once the house has been built, they aren't much help with how to run things. I have a solar system installed, sunsynk 8kw with 2 5.12 batteries. I currently use the heat pump on a timer 5am - 7am (not as hot water as we want) and then 12pm - 15h30pm (hot water is good for an evening shower) - with this set up, I am pulling about 1-2kws from the grid but, I still would like a hot shower in the morning. My problem is, it's winter and the air is much colder, which I am assuming as to why the morning shower is not so hot. I then reached out to the developer today, who says keep the heat pump on constantly because it damages your pipes in winter (compression and expansion with the temperatures) and by running a timer I would use the same amount of electricity than from turning the HP off and on with a timer. The HP pulls around 860-960w, which doesn't sound too bad, but I did try that today and my batteries are already down to 66% at 8pm. (before this recommendation, I would reach 60% just before sunrise and then the grid and PV would run the HP in the am.) I also learnt today that the HP heats about 65l/h. That would mean I would need a good 3 to 3.5 hours in the morning for the water to reach 50deg. I guess what I am asking for in the forum is specifically: How on earth does one get the best benefit from this HP? Does one leave it on the whole day with the geyser (mine is currently off and on non-essentials)? Does one use a timer? If using a timer, how does one set it on the Smart Life App? When turning it off is there a target temperature it should reach? How long should I run it for if timed? Does using a timer damage the HP and the piping in the long run? (We did hear a pop in the ceiling the other night and have seen a slight leak - could it be from this off/on situation?) Any help would do here - I am wrecking my brain trying to figure out the best usage of the HP. Due to the current zero temp very early morning you just need to set the timer to double what was needed a week ago. Developed is wrong. The saved power will still be there as it would just prevent a few about times switching on and off during the night. I switch mine on and off in Centurion at 03h to 05h on cold times like now. It might even need 3hrs. After 13yrs I have never had frozen/burst pipes on mine. You can assist in preventing frozen pipes to perhaps do a short run say 00h to 00h30. I have never done it myself. Essential to have lagging on the outside. COP at 0° can drop to 1 from the 3 level at 20°.
June 6, 20242 yr Author 2 minutes ago, Scorp007 said: COP at 0° can drop to 1 from the 3 level at 20°. Awesome thank you for the response! So running it on a timer is just fine, I just need to adjust the timing to incorporate the weather aspect! I quoted the above because I am not sure what that meant... sorry for my ignorance, new to the renewable energy stuff!
June 6, 20242 yr 27 minutes ago, Ras_al_Ghul said: Awesome thank you for the response! So running it on a timer is just fine, I just need to adjust the timing to incorporate the weather aspect! I quoted the above because I am not sure what that meant... sorry for my ignorance, new to the renewable energy stuff! At a COP of 3 the pump will use 3 times less power to create the same heating affect of the geyser compared to an element. At COP of 1 it will use the same power as element. The lower the ambient temp the lower the COP. There are heat pumps with up to a COP of 6 on larger than household units.
June 6, 20242 yr Water has a specific heat capacity of 4184 Joules of heat (1 calorie) for the temperature of one kilogram of water to increase 1°C. 1 Wh = 1 J/s x 3600s = 3600 Joules. Like @Scorp007 said heat pumps normally has a COP of around 3, so the apparent efficieincy is around 300%. If you have an actual efficiency curve of your heat pump you can calculate the timer switching quite accurately. What is important to remember heat the water just before you need it and insulation is key.
June 6, 20242 yr 5 minutes ago, Ras_al_Ghul said: thanks for the advice... COP stands for?🙈 Coefficient of performance
June 7, 20242 yr Author Thanks guys this helped! Used the timer this morning from 4am - 6:30am and we had boiling hot water. My next task is understanding how to set up the timer on the smart life app. At first the developer told me it was a kwikot HP and I then got a CBI timer switch installed with my solar system, only to find out yesterday that it’s an ITS HP that has WiFi connectivity (first sign of not trusting the developer maybe). I have attached two images of a test run for the timer on the smart life app (which I do like because you can see the temperatures etc). Am I doing it correct? I think my biggest concern is the switching off time, what am I meant to set the target temperature to at the bottom when switching off?
June 7, 20242 yr 10 minutes ago, Ras_al_Ghul said: Thanks guys this helped! Used the timer this morning from 4am - 6:30am and we had boiling hot water. My next task is understanding how to set up the timer on the smart life app. At first the developer told me it was a kwikot HP and I then got a CBI timer switch installed with my solar system, only to find out yesterday that it’s an ITS HP that has WiFi connectivity (first sign of not trusting the developer maybe). I have attached two images of a test run for the timer on the smart life app (which I do like because you can see the temperatures etc). Am I doing it correct? I think my biggest concern is the switching off time, what am I meant to set the target temperature to at the bottom when switching off? Seems fine to me switch on at 4am and if it doesn't reach the target temp of 50°C it will switch off at 7am, if it reaches the target temp before 7am it will switch off. I run my geyser temp at 55°C but if you happy with 50 leave it.
June 7, 20242 yr 15 minutes ago, Ras_al_Ghul said: think my biggest concern is the switching off time, what am I meant to set the target temperature to at the bottom when switching off? Good for you. I would not use a temp higher than 55. Further I think you are lucky that you have a ITS. Mine uses a lot more power (kWh) to get to 60 from 55 than getting from 50 to 55. My reason for using 55 and not 50 is those few degrees is needed when we run a bath or have visitors. Edited June 7, 20242 yr by Scorp007
June 7, 20242 yr Author Thanks again both - I will use your suggestions and try it out tomorrow morning. really appreciate the help 🙂
June 7, 20242 yr Is there a reason why you do not want to set the time to have the heat pump run from say 11:00 (batteries on their way to being fully charged) and off at 17:00 (to prevent draining the batteries when the sun is not shining). That would allow the geyser to reach the max temp. The water should still be quite hot the next morning as it should not loose that much heat from 17:00 to 06:00 the next day. A geyser of 200 liter should be sufficient for more or less 4 people. If needs be you can run it for one hour just before you need water to compensate for the overnight standing loss.
June 7, 20242 yr 2 hours ago, Corné said: Is there a reason why you do not want to set the time to have the heat pump run from say 11:00 (batteries on their way to being fully charged) and off at 17:00 (to prevent draining the batteries when the sun is not shining). That would allow the geyser to reach the max temp. The water should still be quite hot the next morning as it should not loose that much heat from 17:00 to 06:00 the next day. A geyser of 200 liter should be sufficient for more or less 4 people. If needs be you can run it for one hour just before you need water to compensate for the overnight standing loss. It could be left on as suggested but geyser being heated to 60 by sunset can be at 40 after using hot water for cooking and dishes etc. A quick 1 hour in the morning at say below 5° would not increase the temperature much. It does take some time when switched on to work at full capacity.
June 7, 20242 yr Author Agree with Scorp with this. I do normally run it at 11am - 15h30pm but then after a shower or using it a tad bit I’m down to about 40 degrees or so. I would then need that morning run to get me back to that temperature for a morning shower
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