Disappointing solar heater experience

P. Bonnici

Dec 6th 2009, 09:44

1. Check that the solar Panel is facing south,this can be done with a magnetic compass 2. check that the angle of the panel is about 45 degrees to the horizontal , this can be done with a protractor and a spirit level .
If one of these are incorrectly positioned then the efficiency of a solar panel will fall .

Mark Darmanin

Nov 16th 2009, 23:08

If your solar unit is not heating, there must be a valid reason. I am a tech on solar units, I am going to put some absurd requirments I was asked from clients, of which I carried out none.
Connecting a solar unit with a circulating pump. Not applicable. When you do so, you are only remixing warm water with hot water in solar tank, thus lowering the whole water temperature.
Putting the solar unit , behind a tree, Yes, right, a large leafy, beefy tree on the south side. Obvious reason,shade!
And this, the best one. Please put the solar unit where I cannot see it from my pool/the road/my neighbour/my bedroom/the terrace/and a million other excuse.
A solar unit might heat enough water for about 9 to 10 months of the year. Getting something free is definately not without some kind of effort. Adding a timer and relay to the electrical system will help lessen those 'cold' events. Another valid point. I have seen solar units installed where tech put the electrical switch on the washroom roof! Very inconvenient! The switch should be 1st, a double pole switch 20amp and accessable, as required by the IEE .

DVella

Nov 16th 2009, 16:28

@ Robert Micallef . . .

I think there seems to be some confusion in your mind about what solar water heaters are pal, did you try hooking up your plumbing system to the installation shown in that photo by any chance??

I hate to have to point this out but that is a picture of a photovoltaic cell array . . . it produces electricity . . . duh!

Paul Wood

Nov 15th 2009, 18:31

Dr Sir
As a solar contractor in tn, I found your article interesting.It seems you were promised more than you received ,or your system is undersized Here in Tn, I tell customers to expect all of their hot water from the su n for about 8-9 months of the year and then the backup should handle all of your needs, We no longer use seperate tanks to acheive these goals

Michael Asquith

Nov 14th 2009, 02:27

Possibly the most pointless letter I have ever read - especially if Robert is trying to get hot water out of solar panels - it won't work mate! Other than that, yes, winter is cooler than summer, probably all agree on that. My solar water heater works brillianly though, end of. Get a life!

Adrian Zahra

Nov 13th 2009, 20:40

To all those bolstering about the fact that they never did any maintenance on their solar water heater rethink yourself. Solar water heater tanks are normally fitted with a sacrificial anode which is intended to protect the tank from perforation due to oxidation (rust) Unless the sacrificial anode is replaced periodically and with Malta's water quality that would be something around every two to four years depending on model and tank volume you will inevitably end with a useless perforated tank ie: Capital bye bye. It is just a matter of luck and material/build quality if the tank will end up perforated or not. So please refrain yourself. As an engineer I personally think that the most cost/energy efficient system for obtaining hot water is through the use of instantaneous gas heaters. They are fast and super efficient. Only drawback is the refueling using gas cylinders. Also albeit very clean Butane/Propane gases when burnt still releases CO2 which is also of concern nowadays.

Phil Pryce

Nov 13th 2009, 17:58

Here's an idea. Everyone who is very happy with their solar heating installation, why not list the name of the system and contractors who installed it. Likewise for anyone who is unhappy with their system.

Nigel Lawrence

Nov 13th 2009, 17:25

My solar water heater is pumbed into the cold inlet of the geyser which buffers the extreme hot water in summer. In winter the warm water preheats the geyser, so IF there is a need to boost the heat, electrical consumption is very limited. If I should need full heat from the solar supply, there is a by-pass valve which closes off the geyser. A system which works perfectly. My electric bill has plummeted. Also the annual service is a myth. My system has never been serviced and works as well as it did from installation.

DVella

Nov 13th 2009, 17:09

@Robert Micallef Your concerns are understandable but rather than trying to discredit the concept of solar water heaters which you do not seem too knowledgeable in, I'd recommend you examine the specifications and quality of the item you purchased as well as its installation! I've had a solar water heater for the last 6 years and, as claimed by the manufacturer, it paid for itself in just over half that period. I took the additional initiative of installing a time-switch for the back-up heater to ensure that it is not activated during periods when no hot water is required and I enjoy hot water all the year round. For a good quality item which is correctly installed, the actual number of days when no energy at all is collected by the solar panel can be counted on your fingertips in any given year so there is a saving in energy almost throughout the year. Then again, if the unit is a poor quality item, poorly insulated or improperly installed the little benefit gained on less sunny days can be lost. The only time it malfunctioned was when a gasket leak made the insulation wet, leading to large heat losses.

M.O. Micallef

Nov 13th 2009, 16:05

Its a pity that you are not happy. I for one, during the past 12 months haven't switched on the standby electric heater more than twice.

Have an expert check your system. Perhaps your relieve valve opened during the summer releasing steam meaning the water volume from the primary circuit is less than is supposed to be, leading to reduced efficiency. During the Summer months cover the panels with a suitable fabric.

You should check that the solar heater is installed in a place where it is hit by the sun's rays from around at least 1000hrs to 1500hrs. A family of 4 should save around 3 KWHrs a day, from September to June, by means of a solar heater. In my opinion it is better to get water directly from the solar heater having it in parallel with a normal electric water heater which can be isolated and put back in service whenever the need arises.

Good Luck.

Jesmond Farrugia

Nov 13th 2009, 16:01

@Joe Cordina,

I fully agree, most people are extremely satisfied with the performance of their solar heater and when used wisely there are huge savings to be made.

Joe Cordina

Nov 13th 2009, 14:59

It is true that sales people tend to exagarate telling would be customers that solar water heaters = no electricity. However I state that I had purchased one three years ago and found it to be reasonably efficient. The back up system can be programmed to start at a certain temperature. However I do not think that my back up system started up mora than ten or so time throughout the whole of last year. When purchasing a solar heater once has to do his home work well in considering the capacity of the water tank as if this is too small for the size of family it may decrease efficiency a lot

Jesmond Farrugia

Nov 13th 2009, 13:10

Robert, unfortunately what you went to is most probably poor customer service.

No solar heater in the world can give 100% of your hot water for free as the sun does not shine every day throughout the year. Even so, if the solar heater was sized incorrectly to your hot water demands and lifestyle you would not get the full benefit of a solar heater.

M. Debono

Nov 13th 2009, 13:04

@ Robert Micallef

Your article is misleading to say the least.

First of all, I do have a solar heater which is ADEQUATE for my needs, that is, it is large enough with two panels and a 250 litre tank for a family of four.

In a whole year I usually switch it on between 5 - 10 times and usually 30 min would be enough (as you are heating up warm not cold water) - the rest of the year I have HOT water, and I always have HOT water in the mornings.

My consumption (not my bill as prices are going up), has decreased by app. 150kW per month, when comparing a whole year without solar heater, with a whole year with a solar heater.

Figures speak for themselves.

Jason Borg

Nov 13th 2009, 12:58

I would check with a qualified technician as I am the owner of a solar water heater and electricity backup is used not more than 10 times during the year. Usually on a day like today water temperature goes up to 65 deg. C., which is more than adequate. And it stays hot until the tank fills up again at 8.30am

Mark Vassallo

Nov 13th 2009, 12:45

I have had the complete opposite experience, saving almost all of my water heating bill and only needing to use the booster about 5 times a year. About 15 years ago I purchased a 300 litre solar water heater for a family of 2 which then grew to 3. At the time I realised that I could have bought a much smaller unit, but I wanted to save as much electricity as possible. I connected the solar hot water to my kitchen, bathrooms and also to my (dual inlet) washing machine. As a result of this my electricity consumption went down to between 4 and 6 kW.h a day. In spite of a busy lifestyle I made the effort to peek out of my window to check the weather before putting on a large hot wash or before running a full bath. In fact, having a solar panel made me feel a lot more in touch with nature and the elements outside. For some people living in this modern world, this is simply not possible.

K. Dimech

Nov 13th 2009, 11:32

The photograph attached is not of a solar water heater but of a PV cell

Russell Lethbridge

Nov 13th 2009, 11:19

Why the picture of photovoltaics when the letter is about solar water heating?

Anthony Mercieca

Nov 13th 2009, 11:18

My intervention is purely environmental.
While your contributor, Mr. Micallef carries a negative experience of solar heating, my experience - we are a family of four - is totally different. As stated, while in summer the solar water heater is better off sheeted to reduce the water temperature, winter time heated water temperature ranges around 50-60 C (that night time) which is more than decent to use. Imperative, do not use that much warm water prior to going to sleep at night because it is obvious that than water cannot heat up with sun rays. My bills have gone down significantly once I installed the WSH and a gas hob instead of the electrical one .......but still awaiting the MRA refund!!!!!

T Mifsud

Nov 13th 2009, 11:02

My model is 11 years old. We're 4 in the family, washing machine uses solar heated water and is on every other day, kids bath, we shower. A two panel system, never maintained, 200L tank, is great even for winter. On the occasional 3 day overcasts I do switch on the heater for not more than 10 minutes.

I think the method of installation is what makes or breaks the viability of the system.

Nathan Young

Nov 13th 2009, 10:20

We have a three years old solar water heater.Obviously it is not as good in cloudy weather,but switch the backup on for 30 minutes and on a normal day it is enough.This happens around 20 days per year.
In the summer it more than pays for itself. We use a washing machine,wash dishes,take showers,wash the floors etc. all the year,and it is still a big saving.

E.Muscat

Nov 13th 2009, 10:17

Sorry,the picture shows a solar PV system not a solar water heater!A solar water heater does
more than economize on your electric power bill:it minimises the waste of heating water by electrical energy which increases CO2 in the atmosphere:if you are not getting any benefits from your solar water heater than something is wrong with your system and you should have it seen to by a professional.

R. Azzopardi

Nov 13th 2009, 10:02

@Robert Micallef

The method you employ is not a bad method at all. You are feeding your electric geyser with water that has already been warmed to a certain extent. Your electric geyser then brings the temperature up to 60 degrees centigrade or so by using a much smaller heating element than the solar water heater does.

R. Azzopardi

Nov 13th 2009, 10:00

Today's systems are certainly more efficient, however, these solar systems are only cost efficient in the very long term. The purchase price is approximately 10 times that of a normal electric geyser. A normal electric geyser is practically maintenance free, save for the replacement of 1 or 2 thermostats within its lifetime. A solar water heater needs annual maintenance that may cost about 40 euro (i believe that this cost has to be added to the electricity bill to make proper calculations). When properly used, it does make a difference to your electricity but only in the very long run. The advantage is purely environmental. We need to learn that clean energy does not necessarily mean cheap energy. My solar water heater is 10 years old, hence it embraces very old technology. On cold days, I switch it on for exactly 10 minutes, using 1 unit (1kw) of electricity and it gives me enough water for 2 hot showers. It then cools off quite rapidly because it is being refilled with cold water. The newest ones on the market can be programmed to be refilled within a stipulated time bracket, hence retaining heat for longer periods.