Natures own heat pump – vastly more powerful and more untameable than anything we can yet control.

But have you ever wondered why we don’t seem to use the heat of the earth?

We know the earth is hot beneath its crust. Maybe you have luxuriated in a hot thermal spring – or seen the geysers of Yellow Stone National Park? All that heat – where does it all go?

And can we use it?

The idea of heat pumps seems very obvious – yet the technology is fairly complex. But yes, we can use geothermal heat to heat our homes. Or heat pumps can get their heat from another source like natural gas, fossil fuels, oil or electricity.

Why Should We Care About Heat Pumps Now?

Over a third of our energy requirements go to heating and cooling our homes.  So, we need an efficient system. And heat pumps are perhaps the most efficient ways to provide this. They can reduce the energy used by other technologies by around 70%. In fact, heat pumps have the greatest potential of any single system to reduce carbon emissions and hence slow down global warming.

And in the future, as more people are able to afford to cool their homes, the need for a remarkably efficient cooling will become even more important.

Why are Heat Pumps so Efficient?

Heat pumps move heat from one place to another. So as one place heats up, the other place cools down. It is simply a matter of directing the excess heat to the right place.

So we need a heat source – air or the ground. Where geothermal energy is taken from the ground it is then transferred into the home via a coolant-filled ground loop. And the whole process can be reversed to cool a home down.

Here is a fairly simple diagram showing how a heat pump works

simple diagram heat pump
A heat pump works by extracting the energy stored in the ground or water and converts this in a building’s heating system. Heat pumps work on the same principles as a fridge, cooling system, or air conditioning.

 Does Japan Lead the Way?

We can follow the story of heat pumps in Japan:

As early as 1986 the Japanese government founded the Heat Pump and Thermal Storage Centre. It aims were both to find better ways of creating and using heat pumps – but also to educate the public about them.

1995 – the Central Research Institute of Electric Power Industry (CRIEPI) and TEPCO (Tokyo Electric Power Company) started researching heating systems for domestic use. This was important because the Japanese tend to use more hot water than most Europeans – hot baths are very popular in Japan. Average consumption comes to around 429 litres of water per day, at temperatures of 85 degrees Centigrade.  This uses around 34% of the total energy expenditure.

They came up with the idea of using CO2 as a refrigerant for heat pumps. This ensures comfort together with a reduction of emitted CO2. They named it “Ecocute” which means “providing hot water ecologically”. The Japanese government were closely involved.

By the end of the 1990s, they were looking at ways to lessen their reliance on gas, by increasing the use of electricity – derived in part from nuclear power.

They did not limit the research to heat pumps but looked at the wider issues of the carbon cycle from the start. So, they have come up with a very ecological technology.

2001 – the first “Ecocute” heat pumps were sold. Sales continue to rise and over 3.5 million units are in use in Japan.

(This equates the absorption of CO2 by 16,000 square kilometres of forest)

Japan has used sensible incentive schemes to make the cost of installation affordable.

They also made the products suitable for the customers’ specific needs – small houses, cold climates and high seasonal performance. In addition, the techniques used are safe and environmentally friendly.

Fukushima power plant
Earthquake and Tsunami damage, Japan-March 16, 2011: at the Dai Ichi Power Plant, Japan. (credit: DigitalGlobe) http://www.digitalglobe.com

Fukushima Nuclear Disaster

And then in 2011, the Tohoku earthquake happened with the ensuing Fukushima nuclear disaster. This catalysed further research into energy-efficient systems. But the situation regarding the use of nuclear energy is still unclear.

Nowadays, the use of reversible heat pumps is a popular choice. The climate in Japan is a varying one – cold conditions to humid hot temperatures.  Each year around 8.2 million units are sold in Japan.

And research continues. At present they are looking at ways to replace C02 with an even greener refrigerant- Hydrofluorocarbons (HFCs).

So the story in Japan is longstanding, progressive and supported by the government. Innovation and adaptation to local needs has produced a thriving industry.  Japanese homes are comfortably and efficiently heated, relatively cheaply.

And What Has Been Happening in the USA?

At present, there are three most popular fuels which dominate the market in America for heating and cooling. They are:

1. Natural Gas – 49%

2. Electricity – 36%

3. Oil – 5%

Fossil fuel furnaces dominate the hardware side at 54% followed by electric heaters at 26%

The heat pump share of the market is around 11% tho’ the geothermal heat pump market is growing at over 14% -per year and has been since 2009. Geothermal heat pumps are the most efficient type – being up to five times more so than a gas furnace or electrical systems. However, air heat pumps are more popular in America.

Solar rooftop heating is becoming more desirable for Americans. They are looking to use renewable energy sources – and to sell their surplus electricity back to the grid. “Green” products are becoming more in demand. The price of natural gas has been low – at least in part to the controversial fracking method of extraction. But prices for gas are likely to rise in the next few years, although still remain competitive.

What is Holding us Back?

The low price of natural gas – at present if you already have a natural gas furnace then switching to a heat pump does not make economic sense. If you already have solar panels and if they generate enough power to run a heat pump, then it might be worth a change.

Slow innovation – although heat pumps were in operation since the 1940s improvements have been slow tho’ steady.

Installation costs – this can be quite expensive, and it takes a while to recuperate your investment. Trenches may need digging so you need the land available to build a geothermal system. Some financial help might be available which would help with the upfront costs. This varies from region to region. Various companies can help with this.

People are not aware – there is a general lack of knowledge about heat pumps – after all – they don’t sound very exciting! And they are complicated to install.

Permits – you need the right permissions – and every state has its own regulations. Besides, as they are not in common demand, officials may not have the rules clearly to hand, leading to further delays.

Further improvements needed– these include better software to improve efficiency, smaller drills for smaller projects, good thermostats to reduce costs – and of course, data collections and analysis.

What can we Conclude?

So, we are beginning to use the heat of the earth? And there is plenty of it.

Technologies are advancing our ability to use heat pumps – especially the geothermal ones, using our own earth’s heat.

The idea of heat pumps does seem very obvious – and as yet the technology is fairly complex. But yes, we can use geothermal heat to heat our homes.  And even when we get our heat from another source like natural gas, fossil fuels, oil or electricity, a heat pump is efficient.

Using a heat pump to heat our homes reduces the carbon loading on our planet’s atmosphere and helps to reduce the rate of global warming. (And the extra electricity power is an attractive incentive!)

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