Another Government Sustainability Anomaly

6 Comments

1. Luc says:

   February 18, 2010 at 12:58 pm

   From a practical point of view there are a few items worth noting on heat pumps that dont always come through on fact sheets.

   Depending on where you live in Australia, heat pumps might not be such a good solution. From practical personal and work experiences, solar hot water systems prove to be a better environmental solution. Heat pumps have their place but also their problems.
   Even in less sunny places such as southern Victoria it is possible to achieve a 85 – 90% solar fraction from solar hot water systems, a properly sized evacuated tube system will easily achieve this. The volume of gas used to boost such a system is so small that using either natural gas or LPG will create significantly less greenhouse gas emissions than a heat pump system ( gas has about 1/6th of the GHG emissions as coal fired electricity generation).

   Where gas isn’t available, many people have realised that they can turn off their electric element in their solar hot water system for 6 – 10 months of the year with no loss of hot water performance. Effectively these people pay nothing for hot water for most of the year. Likewise with a gas boost system you can turn the gas off to the booster. Unfortunately with an electric heat pump you cant turn it off so no matter what the weather you are paying for hot water.
   Also if you live somewhere cold, electric heat pumps loose significant performance over winter ( the manufacturers don’t tell you this) and end up operating all day to provide your hot water needs, using lots of electricity. Perhaps if you are in QLD a heat pump is an equivalent solution, definitely not in southern Australia.
   Not to mention maintenance. Aside from a small circulating pump there is nothing much to go wrong with a solar hot water system assuming a suitable type of system is chosen for the climate, where as a heat pump has a refrigerator motor, refrigerant, fan and other moving parts that are constantly operating, and you need a refrigeration mechanic to fix it should something go wrong.
   While a heat pump is nice and simple to install beware of lifecycle costs.
   Regardless of the type of system used, if you are replacing an electric storage hot water system with solar or heat pump you will be implementing probably the most cost effective for greenhouse emission reduction action you can take. Sustainability Victoria’s SHW fact sheet (http://www.sustainability.vic.gov.au/resources/documents/SHW_Factsheet_07.pdf) demonstrates that a gas boosted solar hot water system creates only 10% of the annual emissions of an electric storage. Electric boosted solar ( assuming you don’t turn the element off in summer) and heat pumps are around 35%.

   As hot water contributes 25 – 30% of the average household energy consumption, our electricity is so dirty, and electricity prices will rise atleast 25% in the next five years based on recent trends (even without a CPRS) I think the business case for solar is pretty clear.

   These comments are based on both personal experience and years of work experience implementing resource efficiency in commercial and residential buildings.

2. Gail says:

   March 2, 2010 at 12:45 pm

   Thanks for all this info Luc

3. Tony says:

   March 3, 2010 at 8:24 pm

   Hello All,
   I sell both electric and gas boosted solar hot water systems and heat pumps.
   To be honest, I`m not fond of the gas boost units at all. For one, the costs of supply and account fees for either mains or bottle gas is now much much higher than the costs for the small amount of electricity that most electric boost units might use. Since most people have electricity then by using mains gas means that the community must pay for a duplication of an energy supply route. With bottled gas the idea of trucks driving around the countryside to deliver and collect gas bottles is crazy, both for the pollution and noise and costs that such a concept create.
   Why not just use the gas to drive generators at source, and make electricity in the first place.
   As I mentioned the amount of power used in the electric boost systems is very small, and I agree with the above comments about many people turning of the power to the systems boost completely, I have met many clients who have Never had them powered up at all. You can`t beat that !!

4. Sean Hughes says:

   March 12, 2010 at 7:14 pm

   If there is no need for the electric booster, why turn it off ?
   The booster is there to boost the water temperature to above 55 degrees C to kill bacteria, a design requirement for any new hot water storage system in Australia. Bacteria grows well in tepid water, chances are if you only turn on the booster when the water is too cold to shower in without any added cold water, you’ve opened yourself up to the real danger of infection.
   People sometimes get sick and there is no obvious cause . .
   Suggesting that people turn off the booster is bad advice.
   (We could easily change the thermostat on our heat pumps from 60 to 45C and bring down the running cost . . . . )
   Don’t take my word for it check out this link.
   http://www.mid-murray.sa.gov.au/webdata/resources/files/Fact_Sheet_What_is_a_warm_water_system_010509.pdf

5. Marty says:

   May 22, 2010 at 4:23 pm

   I had used a heat pump system with roof panels for over 9 years without any problems and no maintenance at all. Had it on a timer for 4 hours a day from 11am to 3pm. After having to replace tin roof, dismantle the heat pump panels, decided to sell that system and replace it with the more compact outdoor heat pump system. Once again on a 4 hour per day timer. This later model uses about 1kw (electricity input) with 3.2kw (heating water) output by absorbing heat from the atmosphere, even down to -10C (magic of engineering and refrigeration technology).

   At the time we replaced the roof we installed a 1kw solar panel system. In summer, now with only 2 adults living at home (old heat pump supplied hot water for 5 people) the heat pump will operate for average 1 to 2 hours max. In winter it will operate for 2-3 hours per day, and if we have a large shared bath will go for 3+ hours. I live in Katoomba NSW 2780 at 1030 meter altitude with temperatures dropping to 0 over winter. The heat pump has no problems. We have had up to 15 people stay over for a long weekend, a few times, and just took it off the timer, and it supplied showers for everyone all day long.

   We opted for the heat pump mainly due to average yearly figures showing rainfall up to 100+ days per year. I agree, if you have a lot of sunshine and are using the evacuated tube/gas boost system then you really can’t beat that. Although I have heard from people I know who have these systems that in summer (+ hot days) they actually produce too much heated water, and it needs to be released from the tanks, otherwise can cause heat damage to the tubes/system. Nothing is 100% perfect, yet, but we’re moving there step by step.

   There are many people opting for gas instantaneous water heaters. Once again, use is the issue here. If you are away working, travelling etc. then it’s a good investment. If you have a large family, like to have baths or own a spa bath, forget it, your gas bills will be enormous. Although currently gas is about one third the price of electricity (in Sydney )NSW.

   My point? Do your research, ask people who live locally what they use, how much they pay, know what your needs are/will be and base your decisions on solid information, and you will make good choices.

6. Geothermal Heat Pumps says:

   July 26, 2010 at 2:44 am

   Geothermal Heat Pump setup costs are higher than for conventional systems,but the difference is usually returned in energy savings in 3 to 10 years.