Solarhart Solar Water Heater

How about connecting it at the source of your all ready existing hot water supply.

mmmm - well might be good to know if this the the "Tank on Roof" kind, or Tank below - split system as they call it.

But, in either event, I would think you could run PEX from the roof top system, to the nearest gable end of the roof, into the attic area, and then down some chase. Perhaps there is room next to a plumbing vent pipe. The manufacture has several recommended methods for connection to the existing system. I would certainly attempt to follow their recommendation as far as possible.

However, during no load times, these can heat the water to well past safe temps. some kind of tempering valve would be a good idea.

And, I would doubt this will ever supply all of your hot water needs. Unless you live in a very southern location.

Just instal de line in the same line that you have in the actual water heater

It may be better to connect the outlet of the solar water heater tank to the inlet of a regular electric water heater ( with a thermostat ) tank ( of small size ) in series - instead of putting an electric heating element in the large solar heater tank.

This way you will save considerable amount of electricity.

Rajan

Your question cannot be answered effectively without more information about your existing layout.

• How many levels are in your house?
• Does your house have an attic? A basement?
• How are the wall, floors & ceilings of the home constructed? Are they concrete, brick, wood, gypsum board, steel sheet?
• Do you have an existing water heater?
• If so, where is it located relative to the fixtures it serves? Does it serve all the fixtures the new system will serve, or will you need to pipe to additional fixtures?
• If not, to what are the hot water taps connected (you said there were existing pipes on the fixtures)?
• Where is the new heater tank relative to the fixtures it will serve?

There may be a location where you can tap the existing plumbing with minimal wall damage. It may not be possible to do this without some damage, but careful planning can significantly reduce the need for restoration work.

Hello Luyombya,

The timer is a good idea if the electric utility offers a discount at night. It can also conserve electricity if the solar panel is likely to reheat the water without assistance. It looks to me like you would need a 15 Amp relay for the timer contacts.

You should usually connect the solar collector into the existing plumbing where you find the largest diameter hot water pipes. This is usually found only near the old water heater tank. You should be able to avoid drilling through wall tile in the bathrooms and kitchen. What other damage are you concerned about?

You still have to drill through outside walls or through the roof top. If you must go the second way, ask a roofing specialist. Outside wall penetrations are much easier to seal against water leakage than roof top penetrations. If you measure carefully, you can drill from the outside wall directly into an attic, crawl space, or the side of a "partition wall".

I don't know how many people in your house will be using hot water each day. If 4 people bathe in the morning, you may need a tank larger than 180 liters (47 gal) - especially in July. It can get quite cold in July - almost 5 C. You may run out of solar hot water because the tap water is colder. I know some great ways to get more from your solar panel!

All the hot water pipes - old and new - must be well insulated. Insulation is always the best first use of your money. Add insulation blanket around the old water heater tank(s). Replace the sacrificial anodes, if worn out.

Apparently you live in Kigali, Rwanda, you are very close to the equator, but your solar collector model is Tilted! So you will benefit greatly if you reflect sunlight onto the collector with mirrors. This is a good way to get water hotter and hot faster. Mirrors are cheaper than more collectors. If you use mirrors, they will need adjustments and cleaning; so it is safest to keep the collector on the ground, on a deck, or on an accessible horizontal roof. The mirror surfaces should total three times wider than the collector and at least as tall. Secure the mirrors into a tilting frame. The collector should aim north or south. Center the mirror frame at the "foot" of the collector. Tilt the mirror frame so sunlight reflects onto the collector most of the day. The tilt may need adjustment up to twice per month. This is a good interval for cleaning.

Another way to have more hot water is to store more. I would like to emphasize that although your Solahart collector has a built-in storage tank, it is horizontal. Vertical tanks are more efficient storage because of better stratification; the water at the top can get hotter.

I recommend that you keep your old water heater tank, and use it to store more solar heated water. You have several choices of connections from collector to tank: 1) In-series connection (Low efficiency storage), 2) Forced convection (High efficiency) using an electric pump and differential thermostat or 3) Natural convection or Thermo-siphoning (Most efficient). In case 2 and 3, the coldest (hot) water is removed from the tank bottom at the flush/drain valve fitting and convected or pumped into the solar collector. The solar heated water enters the top of the tank at the hot water Outlet. If the collector gets enough energy, the tank can get quite hot from-top-to-bottom. This can potentially double or triple capacity.

In-series storage, low efficiency: You simply connect the solar collector output to the heater's cold water intake or flush-valve port. The heating element will turn on when the solar collector is only supplying warm or cold water. The storage efficiency is low because the solar collector only has the opportunity to heat the tank when hot water is being drawn, and the collector is also hot.

Both forced convection and natural convection (thermo-siphon) storage can raise the tank water temperature all day and far above the set-point of the water heater thermostat. The storage efficiency is so high that a tempering valve is needed to prevent hot water scalding. This adjustable valve mixes hot and cold water to limit temperature downstream.

Forced convection storage means that an (electric) pump is used. This fights against buoyancy when the collector must be mounted higher than the tank. A differential thermostat runs the pump when the collector is hotter than the water at the top of the tank. A check (one-way) valve is needed to prevent back-flow when the pump is off. The pump relies on utility power, unless it runs on a solar-electric panel.

Natural convection (thermo-siphon) storage: You need to study (Google) thermo-siphoning to understand the following requirements: The solar collector has to be Lower than the top of the tank; Right-angle elbows, narrow pipes and distance slow the flow rate (long sweep elbows, short runs and large diameter pipes are best); The further apart they are horizontally, the higher the tank must be to maintain convection speed; Any air that collects in the (hot) loop must escape upward to the faucets, or be drained off by an automatic air bleeding valve; A check valve is needed to prevent back-flow when the collector is colder than the tank. It often makes good sense to bring the storage tank(s) to the solar collector.

To match solar heating to a high-efficiency tank-less gas/oil/propane heater, you may use a tempering valve to automatically switch from solar to conventional heating. (Solar connects to "Cold" on the tempering valve, heater output connects to "Hot".) This works best if the tempering valve is insulated and Very close to the solar collector or solar storage tank or thermo-siphon loop. The valve should be adjusted Hot enough to draw water only from the tank-less heater (without mixing) when the solar heating fails. This requires that the conventional heater be set cooler (say, 49 C) than the mixing valve set-point (say, 54 C).

You may put in a three-way manual valve to select only the solar or conventional heating source.