July 5, 20215 yr Morning all. Please help with my water heating requirements. I would to rely less on Eskom, so i need a optimal water heating system for the house. I currently have 6kw solar array installed and have solar tube that i think are useless as they hardly ever go past 50 degrees in summer let alone in winter. I have recently installed 2 X 49KG gas for the newly converted gas stove. Needs Which options below will cover most of my needs? Stay off Eskom Have enough hot water on sunny days. Have hot water during cloudy and rainy days. Current situation 150L Geyzer Gewiz timer Solar tube Servicing 2 adults and 2 kids - and guests some time 4KW element Connected to solar via coil on Sunsynk Option 1 Current geyzer servicing the master bedroom. Another 200L or 300L servicing the rest of the house relying mostly on solar Remove the solar tube to make way for extra 2 panels to boost production Gas heating system for rainy day. This will barely be used because of the solar production will heat the water during the day. Option 2 No additional geyzer. Gas heating system for the whole house. For cloudy days and normal sunny days. and when i have guests over. and morning showers. Nic over and out.
July 5, 20215 yr 1 hour ago, nightcrawlernic said: Solar tube What exactly is this? We have a 100 or 150 liter (not 100% sure of the size) cylinder with 12 glass evacuated tubes attached for water heating, at this time of year, I can get a hot shower, at times, even need to add some cold water, in summer, it is way too hot (needs an afdakkie), but, this is off gravity fed, low pressure water system, no municipal water and water is fed from a 1000 liter Jojo tank on a 6 or 7m stand... (water cylinder says Afropulse 483 on the side...)
July 5, 20215 yr Author 1 hour ago, Kalahari Meerkat said: What exactly is this? We have a 100 or 150 liter (not 100% sure of the size) cylinder with 12 glass evacuated tubes attached for water heating, at this time of year, I can get a hot shower, at times, even need to add some cold water, in summer, it is way too hot (needs an afdakkie), but, this is off gravity fed, low pressure water system, no municipal water and water is fed from a 1000 liter Jojo tank on a 6 or 7m stand... (water cylinder says Afropulse 483 on the side...) Its the same tubes you have. 12 of them and they facing North.
July 5, 20215 yr You may have too few tubes, I have 24 on a 200l geyser and get to 90degrees in summer sometimes. The system adds cold water to cool it down. In winter not so good but will get to high 40s. This is in Sandton, also north facing.
July 5, 20215 yr 11 minutes ago, nightcrawlernic said: Its the same tubes you have. 12 of them and they facing North. Ok, you are further north than I am, if Centurion is accurate, here we are @95degrees and 50km, from Upington. Are your tubes in shadow for part of the day? This time of year you guys shouldn't have too many clouds and being further north than what I am, I would think you should be able to get a more than comfortable temperature out of the setup, assuming trees don't spoil the suns path to the tubes... mine is actually facing between 15 and 20 degrees real, thus somewhat east of due north. We can not expect to still have warm water on the morning, at 1.2degC this morning, I would have been surprised, but as it is not even ice cubes came out of the pipes this morning here.
July 5, 20215 yr Author Could the problem then be defects on the cubes? Also, i was thinking of taking the tubes out as i don't have enough space for the another set.
July 5, 20215 yr I have a 200 liter hp 20 x evacuated tube self siphoning geyser it is at 15 degrees West from North at about 45 degree angle. On Sunday we did not use water the whole day and it went up to 76 degrees when I got home late the afternoon, today it sits at 65 degrees after the maid has been using water, the worst I’ve seen it was 44 degrees after a very cloudy day. One important thing with evacuated tube geysers are to make sure to apply the heat sink paste to the copper tubes otherwise it will loose lot of heat due to bad contact. I installed my own geyser and made sure and applied the paste thick.
July 5, 20215 yr Is that 6kW or 6kWh tubes? If you reach 50C from cold at say 15C with a 150L geyser then you are getting about 6kWh of energy (0.15x35x1.16=6.1kWh) I would not throw this system away to replace it with PV panels or gas. You probably need 4-6 pv panels to replace or with gas you are going to use a lot of gas. One option is to install a second 200L geyser in series and connect that onto the Inverter system while leaving the first one on the solar tube system. During the day you heat the second one from PV panels and at night it gets replenished from the solar tube geyser not wasting the 6kWh energy. Other option is your option 2 to keep existing system and add gas system (or 2 if bathrooms are not close together) to provide the top up heat. Needs to be a gas heater system capable of doing that. Only problem with this is that your 150L solar tube storage is too small for four/5 people and early morning you will use lots of gas when you run out of hot water. A 200L solar geyser and a few more tubes would be better.
July 6, 20215 yr Author The 6KWh is my solar production capacity. The Geyzer has a 4kw element that i will change to a 2KW.
July 6, 20215 yr On 2021/07/05 at 6:19 PM, Gerrie said: I have a 200 liter hp 20 x evacuated tube self siphoning geyser it is at 15 degrees West from North at about 45 degree angle. On Sunday we did not use water the whole day and it went up to 76 degrees when I got home late the afternoon, today it sits at 65 degrees after the maid has been using water, the worst I’ve seen it was 44 degrees after a very cloudy day. One important thing with evacuated tube geysers are to make sure to apply the heat sink paste to the copper tubes otherwise it will loose lot of heat due to bad contact. I installed my own geyser and made sure and applied the paste thick. where did you get the heatsink paste
July 6, 20215 yr 4 minutes ago, Antony said: where did you get the heatsink paste It came with the geyser in the evacuated tube box, I think it can also be purchased at electronic shops.
October 15, 20214 yr On 2021/07/05 at 9:29 AM, JV0_11_ said: Morning all. Please help with my water heating requirements. I would to rely less on Eskom, so i need a optimal water heating system for the house. I currently have 6kw solar array installed and have solar tube that i think are useless as they hardly ever go past 50 degrees in summer let alone in winter. I have recently installed 2 X 49KG gas for the newly converted gas stove. Needs Which options below will cover most of my needs? Stay off Eskom Have enough hot water on sunny days. Have hot water during cloudy and rainy days. Current situation 150L Geyzer Gewiz timer Solar tube Servicing 2 adults and 2 kids - and guests some time 4KW element Connected to solar via coil on Sunsynk Option 1 Current geyzer servicing the master bedroom. Another 200L or 300L servicing the rest of the house relying mostly on solar Remove the solar tube to make way for extra 2 panels to boost production Gas heating system for rainy day. This will barely be used because of the solar production will heat the water during the day. Option 2 No additional geyzer. Gas heating system for the whole house. For cloudy days and normal sunny days. and when i have guests over. and morning showers. Nic over and out. @JV0_11_Which option did you go with? any regrets? 😁
October 19, 20214 yr Author On 2021/10/15 at 2:55 PM, hoohloc said: @JV0_11_Which option did you go with? any regrets? 😁 No regrets whatsoever. Turned out the developer put 16 tubes on a 200L geyser So i installed 150L geyser(3kw element) and connected it to the 16 tubes + 20 tubes for the 200L(2kw element)and connected them in series. Also added 2 X Geyserwise Max to control the pumps and they own batteries. It works like a charm. Water gets to 65 and 55 daily on average and i even have enough hot water to shower in the morning and all this without even using electricity. On good days i even get to 70 degrees. I have thought of getting a gas water heater for the rainy days but its not a priority at the moment.
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