Heat pump

21 Articles

Arduino Saves Heat Pump

July 16, 2025 by 28 Comments

For home HVAC systems, heat pumps seem to be the way of the future. When compared to electric heating they can be three to four times more efficient, and they don’t directly burn fossil fuels. They also have a leg up over standard air conditioning systems since they can provide both cooling and heating, and they can even be used on water heating systems. Their versatility seems unmatched, but it does come at a slight cost of complexity as [Janne] learned while trying to bring one back to life.

The heat pump here is a Samsung with some physical damage, as well as missing the indoor half of the system. Once the damage to the unit was repaired and refilled with refrigerant, [Janne] used an Optidrive E3 inverter controlled by an Arduino Mega to get the system functional since the original setup wouldn’t run the compressor without the indoor unit attached. The Arduino manages everything else on the system as well including all of the temperature sensors and fan motor control.

With everything up and running [Janne] connected the system to a swimming pool, which was able to heat the pool in about three hours using 60 kWh of energy. The system is surprisingly efficient especially compared to more traditional means of heating water, and repairing an old or damaged unit rather than buying a new one likely saves a significant amount of money as well. Heat pump projects are getting more common around here as well, and if you have one in your home take a look at this project which adds better climate control capabilities. to a wall mount unit.

Better Solid State Heat Pumps Through Science

July 8, 2025 by 22 Comments

If you need to cool something, the gold standard is using a gas compressor arrangement. Of course, there are definite downsides to that, like weight, power consumption, and vibrations. There are solid-state heat pumps — the kind you see in portable coolers, for example. But, they are not terribly efficient and have limited performance.

However, researchers at Johns Hopkins, working with Samsung, have developed a new thin-film thermoelectric heat pump, which they claim is easy to fabricate, scalable, and significantly more efficient. You can see a video about the new research below.

Manufacturing requires similar processes to solar cells, and the technology can make tiny heat pumps or — in theory — coolers that could provide air conditioning for large buildings. You can read the full paper in Nature.

CHESS stands for Controlled Hierarchically Engineered Superlattice Structures. These are nano-engineered thin-film superlattices (around 25 μm thick). The design optimizes their performance in this application.

The new devices claim to be 100% more efficient at room temperature than traditional devices. In practical devices, thermoelectric devices and the systems using them have improved by around 70% to 75%. The material can also harvest power from heat differences, such as body heat. The potential small size of devices made with this technology would make them practical for wearables.

We’ve looked at the traditional modules many times. They sometimes show up in cloud chambers.

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Modeling Home Heating Systems With Circuit Simulation Software

July 1, 2024 by 6 Comments

Electricity flow is generally invisible, silent, and not something that most humans want to touch, so understanding how charge moves around can be fairly unintuitive at first. There are plenty of analogies to help understand its behavior, such as imagining a circuit as a pipe of water, with pressure standing in for voltage and flow standing in for current. But you can flip this idea in reverse and use electric circuits to model other complex phenomena instead. [Oxx], for example, is using circuit theory to model his home’s heating systems.

To build his model, he’s using LTSpice, a free circuit simulation program. Using voltage to model temperature and current to model heat flow, he’s set up a model for his home to compare the behavior of a heat pump and a propane furnace. A switch model already in LTSpice with built-in hysteresis takes the place of the thermostat. Using temperature data for a single day in January [Oxx] can see how each of his two heating systems might behave, and the model for the heat pump is incredibly close to how the heat pump behaved in real life.

The model includes all kinds of data about the system, including the coefficient of performance of the heat pump and its backup electric resistive heater, and the model is fairly accurate at predicting behavior. Of course, it takes a good bit of work to set up the parameters for all of the components since our homes and heating systems won’t be included in LTSpice by default, but it does show how powerful an electric circuit analog can be when building models of other systems. If you’ve never used this program before, we’ve featured a few guides to getting started that you can take a look at.

Thanks to [Jarvis] for the tip!

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Heat Pump Dryer Explained

November 25, 2023 by 98 Comments

Historically, having a washer and a dryer in your house requires “a hookup.” You need hot and cold water for the washer as well as a drain for wastewater. For the dryer, you need either gas or — in the US — a special 220 V outlet because the heating elements require a lot of wattage, and doubling the voltage keeps the current levels manageable. You also need a bulky hose to vent hot moist air out of the house. But a relatively new technology is changing that. Instead of using a heater, these new dryers use a heat pump, and [Matt Ferrell] shows us his dryer and discusses the pros and cons in a video you can below. We liked it because it did get into a bit of detail about the principle of operation.

These dryers are attractive because they use less power and don’t require gas or a 220 V outlet. They also don’t need a vent hose which means they can sit much closer to the wall and take up less space. Heat pumps don’t convert electrical energy into heat like a normal heating element. Instead, it uses a compressor to move heat from one place to another. In this case, the dryer heats the air using the heat pump. That causes water in the clothes to evaporate into the air. The heat pump dryer then uses a second loop to cool the air, condensing the water out so the it can reheat the air and start the whole cycle over again.

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Heat Pump Control That Works

September 4, 2023 by 33 Comments

Heat pumps are taking the world by storm, and for good reason. Not only are they many times more efficient than electric heaters, but they can also be used to provide cooling in the summer. Efficiency aside, though, they’re not perfectly designed devices, largely with respect to their climate control abilities especially for split-unit setups. Many of them don’t have remotely located thermostats to monitor temperature in an area, and rely on crude infrared remote controls as the only user interface. Looking to make some improvements to this setup, [Danilo] built a setup more reminiscent of a central HVAC system to control his.

Based on an ESP32 from Adafruit with an integrated TFT display, the device is placed away from the heat pump to more accurately measure room temperature. A humidity sensor is also included, as well as an ambient light sensor to automatically reduce the brightness of the display at night. A large wheel makes it quick and easy to adjust the temperature settings up or down. Armed with an infrared emitter, the device is capable of sending commands to the heat pump to more accurately control the climate of the room than the built-in controls are able to do. It’s also capable of logging data and integrating with various home automation systems.

While the device is optimized for the Mitsubishi heat pumps that [Danilo] has, only a few lines of code need to be changed to get this to work with other brands. This is a welcome improvement for those frustrated with the inaccurate climate controls of their heat pumps, and since it integrates seamlessly into home automation systems could also function in tandem with other backup heat sources, used in cold climates when it’s too cold outside to efficiently run the heat pump. And, if you don’t have a heat pump yet, you can always try and build your own.

Wind-to-Heat: A Lot Of Hot Air?

June 27, 2023 by 85 Comments

Heating is one of the greatest uses of energy in human society today. Where we once burned logs to stave off the brutal winter chill, now we lean on gas and electricity to warm our homes and keep us safe and toasty. In some colder climates, like the UK, heating can make up 60-80% of total domestic energy demands.

However, there are alternative ways to provide heating. Using wind energy to directly provide heat could be key in this area, using a variety of interesting methods that could have some unique niche applications.

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A Ground Source Heat Pump From An Air Conditioner

March 7, 2023 by 39 Comments

When it comes to lower-energy home heating, it’s accurate in all senses to say that heat pumps are the new hotness. But unless you happen to work with them professionally, it’s fair to say their inner workings are beyond most of us. Help is at hand though courtesy of [petey53], who made his own ground source heat pump for his Toronto house using a pair of window-mounted air conditioning units.

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