Trade Secrets - Solar Hot Water Systems

[TheDigitalWeb]

In Ohio U.S.A., the collectors must face South. Most in the Northern Hemisphere should to achieve optimum efficiency. Good video.

[patrq]

My unckle has that in Poland and even on cloudy days the water gets hot enough to take a hot shover.

[1969626]

Using a solar water heater is good in basically any clyment that you may live in connect the outlet of the solar water heater to a tempering tank then use the water straight from the tempering tank during the wormer months and in the colder months turn on a tankless hot water heater they come in either propane, electric only heat the water your using at that moment and not 24 hours a day 

[munteruk]

Good video but is that info on the electric booster switch actually correct? I thought there were requirements to ensure boosting happened at least once a week to over 60 to control bugs in the tank. A simple manual booster wouldn't necessarily do that.

[tradesecrets2009]

@munteruk

The Australian Standards has looked into this. AS 3500.4 states that water must be heated to at least 60C to avoid legionella growth; HOWEVER the clause below refers to AS3498, which offers some closer detail on the matter

[tradesecrets2009]

Clause 1.9.1 to AS 3500.4:

Heated water storage (Legionella)

Heated water shall be stored and delivered under conditions that avoid the likelihood of the

growth of Legionella bacteria by installing—

(a) a water heater authorized to AS 3498; OR

(b) storing heated water at a temperature not less than 60°C in a hot water storage tank

authorized to AS 3498

So What is AS 3498...read on

[tradesecrets2009]

AS 3498 – 2009: Authorization requirements for plumbing products - Water heaters and hot-water storage tanks

Means shall be provided to inhibit the growth of Legionella bacteria in potable water

within the water-heating appliance. A water-heating appliance will be deemed to

comply with this requirement if it satisfies at least one of the following requirement:

[tradesecrets2009]

(i) For a storage water heater, heat pump water heater or solar water heater, at least

90% of the stored water is heated to 60°C for at least one single period of not

less than 32 min in each 7 day period.

(ii) For a heat pump water heater or solar water heater, at least 45% of the water

contained within the storage tank is heated to a minimum of 60°C daily.

[tradesecrets2009]

(iii) The water heater is operated such that all water is subjected to a temperature dependent minimum exposure period as specified in Table 1 within 7 days before passing through the water-heating appliance’s heated water outlet. TABLE 1 MINIMUM EXPOSURE PERIOD Temperature Minimum exposure period 70°C or greater 1 s 66°C 2 min 60°C 32 min 55°C 6 h

[tradesecrets2009]

So, THIS MEANS: it is deemed sufficiently safe to use a manual booster solar system as:

a) it is highly unlikely that the water would remain unused in the tank for a period of seven days; and

b) if it was left in the tank for this period it’s highly likely the water would be heated to the temperatures the conditions specified in either i), ii) and iii) above.

It would be worth telling the householder to turn on booster upon return from a holiday, if cold/cloudy during the previous 7days.

[tradesecrets2009]

So, THIS MEANS: it is deemed sufficiently safe to use a manual booster solar system as:

a) it is highly unlikely that the water would remain unused in the tank for a period of seven days; and

b) if it was left in the tank for this period it’s highly likely the water would be heated to the temperatures the conditions specified in either i), ii) and iii) above.

It would be worth telling the householder to turn on booster upon return from a holiday, if cold/cloudy during the previous 7days.

[powtrekker85]

Great learning for new installers and householders. Thanks for the resource