History of the heat pump

Before we dive into the future of the heat pump, let’s learn a bit about its history.

Did you know that the technology behind modern heat pumps was invented in 1748? Even though heat pumps can’t hold a candle to evaporative cooling, which was first used by the ancient Egyptians around 3000 years ago, they have still been around a surprisingly long time. However, the first practical heat pump design wasn’t perfected until around 100 years after the technology was invented, and the first large scale installation of a reversible heat pump wasn’t until 1951. It provided both winter heating and summer cooling to the Royal Festival Hall in London, was powered by coal gas (also known as town gas), and used the river Thames as a heat sink.

It wasn’t until the 1990s, when utility companies in the Northwestern US realized the efficiency potential of these systems, that they began to be adopted on a wide basis by American consumers.

This diagram depicts the layout of a Household Geothermal Heat Pump

How does a heat pump work?

A heat pump uses the same technology you see in your household refrigerator – it transports heat from one area (the inside of your fridge) to another (the air of your kitchen). Household heat pumps have an indoor coil, an outdoor coil, a compressor, and one key feature that your refrigerator lacks – a reversing valve. During the summer, the outdoor coil serves as the condenser, while the indoor coil serves as the evaporator. This way, heat is transported from inside your home and deposited into the ground outside. When winter comes around, simply flip the reversing valve. The outdoor coil becomes the evaporator, the interior becomes the condenser, and heat is transported from the ground outside and deposited inside your home.

Check back soon for The Future of the Heat Pump, Part 2