Hi, so often, we had to wait for minutes before we had the hot water in bathroom. Now, we asked the builder to install the recirculating pump with timer in order to make it ready to use during morning and evening peak hours in the new house. Any thought about this builder reply? Should we need a heat pump system to make it worked?
Quote from the builder
"I have been thinking about the solar hot water service since we last spoke about it and come across another possible solution.
Currently, the solar hot water service has been allocated to serve the first floor, however as explained, we cannot fit a recirculating pump to a standard solar hot water service. A recirculating pump allows hot water to be circulated around the home so that the time for hot water to reach a particular outlet is reduced.
You have told me that you would therefore like to have the standard storage hot water service the first floor as this would allow for water to be recirculated upstairs and therefore reduce the time for hot water to reach an outlet.
Solar water can only be connected to a recirculating pump if a secondary tank is installed and as mentioned to you previously, this increase the cost of the system by about $5-6 thousand dollars.
The other possible solution is to install a heat pump hot water system. This type of system is classified as a solar hot water system but does not require solar panels to be installed on the roof nor does it require a gas booster. They are quite efficient and we have installed or provisioned for a couple of these units recently with success. The good thing with these systems is that they can be connected to a recirculation pump. There will also be a saving of about $3,000.00 which can be used for other things. (A possible disadvantage is that like the standard storage hot water service, the heat pump is not a continuous hot water service – that is you have to wait for it to heat up. The standard solar service has a gas booster and thus can supply continuous hot water).
I have attached a brochure of the system we propose for you to consider. Please let me know if you are interested.
If however you would prefer to simply switch the allocation of hot water systems, so that the solar unit is connected down stairs and the storage system is connected upstairs, please reply to this email with words to the effect that you would like me to proceed with this change in allocation of hot water units."
Many Thanks,
Recirculating Hot Water Service
Page 1 of 1
I have a reticulated domestic hot water setup at time with a circulation pump connected to an instantaneous gas hot water boiler. It's actually an combi condensing boiler for my hydronic setup but I'm using the secondary loop for domestic hot water. I set up a recycle timer to run the pump for 3 minutes every 15 minutes and this is adequate to provide almost instant hot water out of the tap. The boiler only ignites and fires if the water circulating through is below 50 degrees or so and I've watched it only fire a couple of time for short periods (less than 20 seconds) in the 3 minutes on time. The best practice is to get all the hot water pipework insulated with pipe insulation (9mm wall is adequate but thicker will obviously provide greater insulating properties) and run the ring main around so that you can keep all your branches as short as practically possible. This will ensure that you only need to drain the water out of the branch pipe before you get hot water. I can get hot water after running 2 coffee mugs of water.
I don't have solar hot water so cannot comment if this would be suitable. I see how reason why it wouldn't work with a storage hot water service as a lot of commercial buildings run reticulated domestic hot water off storage water heaters. My only reservation with a heat pump hot water system is if the compressor is not inverter driven or soft started, the life of the compressor could be reduced with the frequent starting and stopping as the hot water services tries to maintain hot water at set point.
If the plumber who is going to do this is worth any salt he'll know that you'll require tempering valves for all sanitary fixtures to provide a maximum of 50 degrees hot water to prevent scalding. You will also need to run the hot water at 60 degrees in the main loop as it is in essence classed as a hot water storage medium to prevent the propagation of legionella.
hth
I don't have solar hot water so cannot comment if this would be suitable. I see how reason why it wouldn't work with a storage hot water service as a lot of commercial buildings run reticulated domestic hot water off storage water heaters. My only reservation with a heat pump hot water system is if the compressor is not inverter driven or soft started, the life of the compressor could be reduced with the frequent starting and stopping as the hot water services tries to maintain hot water at set point.
If the plumber who is going to do this is worth any salt he'll know that you'll require tempering valves for all sanitary fixtures to provide a maximum of 50 degrees hot water to prevent scalding. You will also need to run the hot water at 60 degrees in the main loop as it is in essence classed as a hot water storage medium to prevent the propagation of legionella.
hth
I have a reticulated domestic hot water setup at time with a circulation pump connected to an instantaneous gas hot water boiler. It's actually an combi condensing boiler for my hydronic setup but I'm using the secondary loop for domestic hot water. I set up a recycle timer to run the pump for 3 minutes every 15 minutes and this is adequate to provide almost instant hot water out of the tap. The boiler only ignites and fires if the water circulating through is below 50 degrees or so and I've watched it only fire a couple of time for short periods (less than 20 seconds) in the 3 minutes on time. The best practice is to get all the hot water pipework insulated with pipe insulation (9mm wall is adequate but thicker will obviously provide greater insulating properties) and run the ring main around so that you can keep all your branches as short as practically possible. This will ensure that you only need to drain the water out of the branch pipe before you get hot water. I can get hot water after running 2 coffee mugs of water.
I don't have solar hot water so cannot comment if this would be suitable. I see how reason why it wouldn't work with a storage hot water service as a lot of commercial buildings run reticulated domestic hot water off storage water heaters. My only reservation with a heat pump hot water system is if the compressor is not inverter driven or soft started, the life of the compressor could be reduced with the frequent starting and stopping as the hot water services tries to maintain hot water at set point.
If the plumber who is going to do this is worth any salt he'll know that you'll require tempering valves for all sanitary fixtures to provide a maximum of 50 degrees hot water to prevent scalding. You will also need to run the hot water at 60 degrees in the main loop as it is in essence classed as a hot water storage medium to prevent the propagation of legionella.
hth
I don't have solar hot water so cannot comment if this would be suitable. I see how reason why it wouldn't work with a storage hot water service as a lot of commercial buildings run reticulated domestic hot water off storage water heaters. My only reservation with a heat pump hot water system is if the compressor is not inverter driven or soft started, the life of the compressor could be reduced with the frequent starting and stopping as the hot water services tries to maintain hot water at set point.
If the plumber who is going to do this is worth any salt he'll know that you'll require tempering valves for all sanitary fixtures to provide a maximum of 50 degrees hot water to prevent scalding. You will also need to run the hot water at 60 degrees in the main loop as it is in essence classed as a hot water storage medium to prevent the propagation of legionella.
hth
Thanks for the information, how much eventually cost for both recirculated hot water and hydronic set up if you don't mind I ask? Is there hydronic heating you refer to? Very pricey. I would like to have it as kids had a bit allergy issue.
The cost of the hydronic was ~$14k for 9 panels, 2 towel rails and the boiler installed. It was minus a thermostat/controller as I was supplying my own. Yes I do agree it's much more pricier than ducted heating but it's a nicer heat overall and my kids also have allergies so with that I couldn't put a price on what's best for my kids.
The reticulated hot water was ~$1600 variation on top of what the plumber had originally quoted for my reno/extension and included running the ring main around to keep the branches as short as possible, lagging all the pipework, the circulation pump and the additional tempering valves. In addition to this I had a few hundred $$$ for a small switchboard enclosure and switchgear required to cycle the pump on and off. When I find where I misplaced it, I'll be adding a time switch to the control to lockout the pump operation in the middle of the night and during the day when no one is home.
The reticulated hot water was ~$1600 variation on top of what the plumber had originally quoted for my reno/extension and included running the ring main around to keep the branches as short as possible, lagging all the pipework, the circulation pump and the additional tempering valves. In addition to this I had a few hundred $$$ for a small switchboard enclosure and switchgear required to cycle the pump on and off. When I find where I misplaced it, I'll be adding a time switch to the control to lockout the pump operation in the middle of the night and during the day when no one is home.
The cost of the hydronic was ~$14k for 9 panels, 2 towel rails and the boiler installed. It was minus a thermostat/controller as I was supplying my own. Yes I do agree it's much more pricier than ducted heating but it's a nicer heat overall and my kids also have allergies so with that I couldn't put a price on what's best for my kids.
The reticulated hot water was ~$1600 variation on top of what the plumber had originally quoted for my reno/extension and included running the ring main around to keep the branches as short as possible, lagging all the pipework, the circulation pump and the additional tempering valves. In addition to this I had a few hundred $$$ for a small switchboard enclosure and switchgear required to cycle the pump on and off. When I find where I misplaced it, I'll be adding a time switch to the control to lockout the pump operation in the middle of the night and during the day when no one is home.
The reticulated hot water was ~$1600 variation on top of what the plumber had originally quoted for my reno/extension and included running the ring main around to keep the branches as short as possible, lagging all the pipework, the circulation pump and the additional tempering valves. In addition to this I had a few hundred $$$ for a small switchboard enclosure and switchgear required to cycle the pump on and off. When I find where I misplaced it, I'll be adding a time switch to the control to lockout the pump operation in the middle of the night and during the day when no one is home.
Agree with you, there is no price can compare on the health of family. I should at least use it for all bedrooms.
Back on topic, how did you go with your builder in getting a reticulated hot water setup added to your build?
In my experience I have found that recirculating hot water systems for domestic dwellings are very inefficient. You lose a lot of heat energy from heat loss in the pipes, so the system is constantly circulating hot water around the house, that then loses the heat, and so the cycle goes. I have monitored energy usage in this situation and then monitored it with the circulating pump switched off, and it was a significant difference in energy consumption (about 30-40% higher with the circulation pump system operating).
With that said, you could operate the circulating pump on a 7 day timer so that it is only circulating during the hours that you are likely to be using hot water (for example, for a typical family household, operate in the mornings and evenings during the week, and from day 5am - 10pm on weekends).
It would be much lower cost to design the house and the plumbing system so that hot water pipe runs are minimised (i.e. locate the hot water system as central as possible to the hot water fixtures and to insulate the hot water lines with armaflex or similar.
Our house is single level and quite a "sprawling" U-shaped layout. The solar hot water system is directly above the kitchen, laundry and the two other bathrooms, but the hot water pipe run from the solar hot water system to our ensuite is about 30 metres. It takes 40-50 seconds to get hot water to the ensuite. What I did was have a small Steibel Eltron instantaneous electric system installed in series with the hot water line in the ensuite, so that it heats the "dead leg" of cold water until the hot water from the central system gets to that point, then the instantaneous unit switches off.
With that said, you could operate the circulating pump on a 7 day timer so that it is only circulating during the hours that you are likely to be using hot water (for example, for a typical family household, operate in the mornings and evenings during the week, and from day 5am - 10pm on weekends).
It would be much lower cost to design the house and the plumbing system so that hot water pipe runs are minimised (i.e. locate the hot water system as central as possible to the hot water fixtures and to insulate the hot water lines with armaflex or similar.
Our house is single level and quite a "sprawling" U-shaped layout. The solar hot water system is directly above the kitchen, laundry and the two other bathrooms, but the hot water pipe run from the solar hot water system to our ensuite is about 30 metres. It takes 40-50 seconds to get hot water to the ensuite. What I did was have a small Steibel Eltron instantaneous electric system installed in series with the hot water line in the ensuite, so that it heats the "dead leg" of cold water until the hot water from the central system gets to that point, then the instantaneous unit switches off.
Reticulated hot water systems are only inefficient energy wise in domestic dwellings if the pump is constantly running. You can increase the overall efficiency with the use of timers to cycle the pump on and off and like you suggest, timeclocks to only run the system at certain time periods. I've monitored my own gas consumption over the last 12 months with my instantaneous hot water with circulating pump system compared to a 12 month period prior to my reno where I had an old storage hot water service and my consumption now is less and costs less. Considering the tariff and service charge has gone up since then, this is considerable. I'm sure I'll get better savings when I find where I misplaced that timeclock I am intending to install to only allow the pump to run during certain time periods where it will still only cycle for 3 minutes every 15 minutes to maintain the temperature of the ring main.
You can't stop heat loss out of the pipes but you can reduce it by insulating all the pipework. If you go into the decision to get a reticulated as an afterthought then that's where you'd run into issues with heat losses from the pipework, increased energy consumption, etc. This should be something to be planned from the beginning and discussed with the plumber installing it who should advise and recommend things such as insulating the pipework, keeping branches as short as possible, etc.
There's nothing wrong with how you've setup your hot water though I probably wouldn't do it that way myself. Like anything, horses for courses.
You can't stop heat loss out of the pipes but you can reduce it by insulating all the pipework. If you go into the decision to get a reticulated as an afterthought then that's where you'd run into issues with heat losses from the pipework, increased energy consumption, etc. This should be something to be planned from the beginning and discussed with the plumber installing it who should advise and recommend things such as insulating the pipework, keeping branches as short as possible, etc.
There's nothing wrong with how you've setup your hot water though I probably wouldn't do it that way myself. Like anything, horses for courses.
Yeah it's a bit unorthodox, but the layout of the house and the fact that it's 50 years old with nowhere to run new pipes was not really conducive to any other viable solution. The ensuite is miles away from the other bathrooms, kitchen and laundry. The setup works really well and only costs a few cents per day in electricity. The stiebel eltron units are variable power, so they only use as much energy as required to get the temperature rise required (e.g. from 25 degrees C to 60 degrees C), once the hot water from the solar HWS tank gets to the unit (usually within 30-40 seconds and well over 60 degrees C), it switches off completely. If it has not been long since hot water was last used, the water in the lines might be at 35-40 degrees, so it only needs to use enough energy to get the water to rise 20-25 degrees, so with insulated pipes the instantaneous heater doesn't have to do much work at all.
Reticulated hot water systems are only inefficient energy wise in domestic dwellings if the pump is constantly running. You can increase the overall efficiency with the use of timers to cycle the pump on and off and like you suggest, timeclocks to only run the system at certain time periods. I've monitored my own gas consumption over the last 12 months with my instantaneous hot water with circulating pump system compared to a 12 month period prior to my reno where I had an old storage hot water service and my consumption now is less and costs less. Considering the tariff and service charge has gone up since then, this is considerable. I'm sure I'll get better savings when I find where I misplaced that timeclock I am intending to install to only allow the pump to run during certain time periods where it will still only cycle for 3 minutes every 15 minutes to maintain the temperature of the ring main.
You can't stop heat loss out of the pipes but you can reduce it by insulating all the pipework. If you go into the decision to get a reticulated as an afterthought then that's where you'd run into issues with heat losses from the pipework, increased energy consumption, etc. This should be something to be planned from the beginning and discussed with the plumber installing it who should advise and recommend things such as insulating the pipework, keeping branches as short as possible, etc.
There's nothing wrong with how you've setup your hot water though I probably wouldn't do it that way myself. Like anything, horses for courses.
You can't stop heat loss out of the pipes but you can reduce it by insulating all the pipework. If you go into the decision to get a reticulated as an afterthought then that's where you'd run into issues with heat losses from the pipework, increased energy consumption, etc. This should be something to be planned from the beginning and discussed with the plumber installing it who should advise and recommend things such as insulating the pipework, keeping branches as short as possible, etc.
There's nothing wrong with how you've setup your hot water though I probably wouldn't do it that way myself. Like anything, horses for courses.
Hi, our builder advised us that heat pump will not work on solar hot water, we might have to use normal hot water storage without gas boaster. the storage Hot water service HWS which was originally to service the ground floor has been re-purposed to serve the 1st floor. The proposed heat pump HWS will now service 1st floor. Both HWS will be fitted to recirculating pumps. What do you think this setup? otherwise, builder said that will be costly. I also heard the timer could damage the heat pump if switch on and off; but it shouldn't be cause too much problem as it only use timber twice in morning and night daily.
Thanks,
Gary
I don't think the heat pump HWS is going to be too flash when used with a circulation pump. If you disregard the recycle timer I'm using and use purely a time clock, when it's running in the morning and at night only, the circulated water will still call the heat pump on and run the compressor if the return water is below its setpoint. I'll try to detail an example below if that helps to explain what I mean.
Time clock allows operation between 5am - 8am so the circulation pump is running constantly during that time.
Heat pump starts at 5am and switches off at 5.20am when the hot water is 65 degrees.
With heat losses, the return water temperature drops to 50 degrees at 5.45am and the heat pump starts again
Heat pump switches off at 5.50am when the hot water is 65 degrees
At 6.15am the return water temperature drops to 50 degrees and heat pump switches on
At 6.20am heat pump switches off again
At 6.50am heat pump switches on
At 7.05am heat pump switches off
And so will continue until 8am when the time clock stops the circulation pump from operating. That's the sort of starting and stopping I was referring to in my original reply.
Maybe contact the manufacturer of the heat pump HWS you intend of using and check if their system is compatible with a reticulated hot water system.
hth
Time clock allows operation between 5am - 8am so the circulation pump is running constantly during that time.
Heat pump starts at 5am and switches off at 5.20am when the hot water is 65 degrees.
With heat losses, the return water temperature drops to 50 degrees at 5.45am and the heat pump starts again
Heat pump switches off at 5.50am when the hot water is 65 degrees
At 6.15am the return water temperature drops to 50 degrees and heat pump switches on
At 6.20am heat pump switches off again
At 6.50am heat pump switches on
At 7.05am heat pump switches off
And so will continue until 8am when the time clock stops the circulation pump from operating. That's the sort of starting and stopping I was referring to in my original reply.
Maybe contact the manufacturer of the heat pump HWS you intend of using and check if their system is compatible with a reticulated hot water system.
hth
I don't think the heat pump HWS is going to be too flash when used with a circulation pump. If you disregard the recycle timer I'm using and use purely a time clock, when it's running in the morning and at night only, the circulated water will still call the heat pump on and run the compressor if the return water is below its setpoint. I'll try to detail an example below if that helps to explain what I mean.
Time clock allows operation between 5am - 8am so the circulation pump is running constantly during that time.
Heat pump starts at 5am and switches off at 5.20am when the hot water is 65 degrees.
With heat losses, the return water temperature drops to 50 degrees at 5.45am and the heat pump starts again
Heat pump switches off at 5.50am when the hot water is 65 degrees
At 6.15am the return water temperature drops to 50 degrees and heat pump switches on
At 6.20am heat pump switches off again
At 6.50am heat pump switches on
At 7.05am heat pump switches off
And so will continue until 8am when the time clock stops the circulation pump from operating. That's the sort of starting and stopping I was referring to in my original reply.
Maybe contact the manufacturer of the heat pump HWS you intend of using and check if their system is compatible with a reticulated hot water system.
hth
Time clock allows operation between 5am - 8am so the circulation pump is running constantly during that time.
Heat pump starts at 5am and switches off at 5.20am when the hot water is 65 degrees.
With heat losses, the return water temperature drops to 50 degrees at 5.45am and the heat pump starts again
Heat pump switches off at 5.50am when the hot water is 65 degrees
At 6.15am the return water temperature drops to 50 degrees and heat pump switches on
At 6.20am heat pump switches off again
At 6.50am heat pump switches on
At 7.05am heat pump switches off
And so will continue until 8am when the time clock stops the circulation pump from operating. That's the sort of starting and stopping I was referring to in my original reply.
Maybe contact the manufacturer of the heat pump HWS you intend of using and check if their system is compatible with a reticulated hot water system.
hth
Thanks, I should find out more about the heat pump.
The builder suggested us to replace solar hot water with heat pump system, it also fit with recirculating pumps. However, I read some articles that suggested the unit is only work well in warm, humi climate; does it mean the performance in Melbourne winter will be halved? Any thought? I sent your set up system to the builder, but seems they reckon that we are different.
Yeah usually in low ambient temperatures (dead of winter in Melbourne) heat pumps will struggle to draw heat out of the air and ice forms on the outdoor coil after prolonged operation.
I've had a quick look and Sanden, Rinnai, Rheem, Chromagen and Dux heat pumps all don't recommend installation in Melbourne/Victoria in general as you'll likely be using the booster element a fair bit which defeats the purpose of getting a heat pump. Solahart works down to 3-5 degrees and utilizes the booster element after that so also not that flash. The Stiebel Eltron heat pump is equipped with active defrost so would be my recommendation though I'd still check with them on compatibility with circulation pumps.
My experience with finding builders was that most did not want to do anything that was out of the norm for them.
I've had a quick look and Sanden, Rinnai, Rheem, Chromagen and Dux heat pumps all don't recommend installation in Melbourne/Victoria in general as you'll likely be using the booster element a fair bit which defeats the purpose of getting a heat pump. Solahart works down to 3-5 degrees and utilizes the booster element after that so also not that flash. The Stiebel Eltron heat pump is equipped with active defrost so would be my recommendation though I'd still check with them on compatibility with circulation pumps.
My experience with finding builders was that most did not want to do anything that was out of the norm for them.
Yeah builders often don't really know what they're talking about with electrical/mechanical stuff and don't like departing from their usual setup.
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