Finding the chase and cutting to it

Throughout time, humans have celebrated life’s big events. Sometimes lavishly, sometimes simply.

Every year, we have a barbecue while a classic car run goes past our back garden. We are not the only ones, and on a sunny (or at least dry) day, the crowds lining the streets are almost as entertaining as the cars, push bikes, electric vehicles of all ages, tractors, fire engines and police cars, motorbikes, and lorries going past.

As I took a couple of days to prep for the event this year, it’s one of the few where I can honestly say “no hydrocarbons were burnt making these rolls”. In fact, I did slightly better than that as mostly the sun was shining while I baked, so we got to enjoy 100% of that power rather than dropping 7% in the round trip from the battery!

Tonight, we are using the last of the excess stored in our battery from the past few days. It rarely means we are 100% off grid, our battery system is a little slow at switching to the store when needs change but it doesn’t do a bad job.

Of course, now we are entering summer, our generating potential is being affected by other factors. The trees being in full leaf makes quite an impact: no it doesn’t mean we wish those trees were not there. A healthy tree does far more for reducing carbon dioxide than our photovoltaics do! A pair of mature maples (like the ones we’re talking about) take ~50kg of CO2 a year out of the air. Our 4kW system saves around 700kg being produced a year for our electricity.

Er, hold on there, shouldn’t we have more panels less trees?

No, we shouldn’t. The panels mean we produce less, but trees actually reduce what is in the atmosphere. The estimate is that plants and oceans absorb roughly 30% of the CO2 people currently produce.

In fact, if we can reduce our carbon production to a low enough level, there is a chance plants can help us recover much more quickly – though we are still talking hundreds of thousands of years to get back to pre-industrial levels.

Something that took 150 years to achieve would take hundreds of thousands of years to recover from, if we could reduce our carbon footprints enough to reach zero.

We can all make a diference here. Drive less, reduce energy usage, reduce waste, switch to a higher percentage of plant based foods are all things all of us can do.

Oil prices should be higher as it does change how people behave.

While researching this blog, one of my biggest findings has been that homes in rural areas are much more likely to make the switch to heat pumps than homes in towns. 75% of heat pump installs were in rural areas compared to 25% in towns. The volatility of oil prices are thought be a leading factor in those decisions.

I know you say heat pumps are super efficient but you can’t win!

The laws of thermodynamics are irrefutable; and no, heat pumps do not break these fundamental laws. The first law of thermodynamics says you cannot get more heat out of a system than you put in (you can’t win). In heat pump terms, this isn’t efficiency but the coefficient of performance and that is a better way to think of the figures – an efficient heat pump achieves a coefficient of performance of 3.5 or greater over the entire year.

How can a heat pump be more than 100% efficient? This is what I understand. Heat pumps look amazing because for each unit of energy used by them, between three and ten to twelve units of heat (all measured in kWh) are achieved round the system.

Heat pump systems do lose heat: radiators and heated floors work by that very principle. By the laws of thermodyanamics: you can’t win and you can’t break even. In terms of electricity put in and heat delivered round the system, it does look as if that is happening – until we realise that our “loss” is the unit of electricity we are using to pull the heat out of the atmosphere and send it round our heating circuits.

We are not beating the odds because we are not creating heat, merely moving it from the air into our heating water and hot water.

If we can use home or micro-generation to supply the energy for the heat pump, and our homes insulation so we enjoy as much of that heat as possible, we are looking at a brilliant way of keeping our homes warm and our water hot.

Having had one for a year in the Suffolk Surburbia, I wouldn’t go back.