Gorgeous Green House

The Renovation Journey of a 1940’s ‘Traditional’ to 2015 ‘Contemporary, Green & Gorgeous’


Everything Has A Season

I found this on another site, Author is unknown but I am re-posting it as a public service for home/backyard gardeners and those involved in raising small livestock.

young-pigsA farmer had five female pigs. Times were hard, so he decided to take them to the county fair and sell them. At the fair, he met another farmer who owned five male pigs. After talking a bit, they decided to mate the pigs and split everything 50/50. The farmers lived sixty miles apart. So they agreed to drive thirty miles each, find a field in which to let the pigs mate.

The first morning, the farmer with the female pigs got up at 5 A.M., loaded the pigs into the family station wagon, (which was the only vehicle he had) and drove the thirty miles. While the pigs were mating, he asked the other farmer, “How will I know if they are pregnant?”

The other farmer replied, “If they’re lying in the grass tomorrow morning, they’re pregnant. If they’re in the mud, they’re not.”

The next morning the pigs were rolling in the mud. So he hosed them off, loaded them into the family station wagon again and proceeded to try again. This continued each morning for more than a week and both farmers were worn out.

The next morning he was too tired to get out of bed. He called to his wife, “Honey, please look outside and tell me whether the pigs are in the mud or in the grass.”

Neither,” yelled his wife, “they’re in the station wagon and one of them is honking the horn.”

Merry Christmas and a Happy New Year


Solar Geysers vs Heat Pumps: cheap can be expensive!

Eskom (South Africa’s national energy provider) has recently conducted a study comparing solar geysers to heat pumps

Solar geyser

The conclusions drawn from the study were:

  • Heat pumps achieve at least 80% of the savings possible with a comparable solar water heating system, but at far lower installation cost.
  • Heat pumps are a cost effective technology for heating water in commercial applications.

They offer this graph to show the reduced payback period for heat pumps attributing it to the lower installation costs of heat pumps.

Pay back Solar Geysor vs Heat Pump (according to ESKOM)

Pay back Solar Geysor vs Heat Pump (according to ESKOM)

This appears to be a reliable endorsement of heat pumps, but here is what they don’t tell you:

  • Eskom do subsidise heat pumps, but do absolutely no performance testing on them.  Currently there are no heat pumps in South Africa with the SABS (South African Bureau of Standards) mark of approval. In the solar industry, all products on the subsidy programme had to be tested against SANS 1307 prior to being permitted on the programme.
  • Heat pump providers claim they will save you 60% on your water bills.  Possible yes, if every day was an optimum weather day with low humidity and high ambient temperatures.  It is not realist for providers to claim a ratio of the heating provided over the electrical energy consumed (COP) of 3:1, it will average out at 1:1.5.  This assumes you have purchased a quality machine and the large majority of the cheap heat pumps were actually designed as under floor heaters!   To achieve water temperature of 55 degrees the pressure has to be raised from the 18 bar (which it was designed for) to the 38 bar setting.  Making the compressor work at this level is a bit like placing a brick on the gas pedal of a V8.  It’s going to fail!
  • Heat pumps require a sanitary condenser.  This ensures that in the event of a failure no contamination of your water occurs.  When this happens in heat pumps without condensers, the smell of hot oil lingers in the hot water taps.  For this reason Australia and New Zealand have banned non sanitized condenser units, no such restriction are applied in South Africa!
  • Heat pumps are cheaper than solar geysers. Yes, but you still need to buy or connect your heat pump to an electrical geyser and that cost is seldom factored in to the comparison.
  • Heat pump suppliers will tell you that because the sun doesn’t shine at night you will have a cold shower in the morning.  Not true!  A good quality solar system, correctly sized, is designed to supply 24hrs of hot water from 6hrs of sunshine.
  • A final scary scenario to consider:  you purchase a heat pump which fails.  Your phone your insurance company who refute the claim because it in a non- SABS product.  The plumber has disappeared because he bought a container from the east and is getting so many phone calls he’s ‘shut up shop’ and disappeared.  Finally you phone Eskom, as your logic says they’ve provided a subsidy therefore perhaps can provide some sort of relief. They will refer you to point 6 on the subsidy form which states that they take no responsibility for the performance or quality of your heat pump!
polygala virgata

Polygala virgata currently in flower. Beautiful delicate shrub, perfect for urban gardens.

You then go out and purchase a solar geyser!


The South African Mechanical Engineer VOL 62