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Archive for the category “space heating”

TNO & TUE Heat Battery

Dutch video, English subs

TNO and TU/e have developed a brand new device principle and a breakthrough material, in which the heat is stored. Together they form the heat battery. It is so small that it fits into the limited space available in most homes. The breakthrough material is a salt composite, with K2CO3 (potassium carbonate) as the base material.

The heat battery uses a so-called thermochemical principle. The heat battery for the home is based on two components: water and a salt hydrate. As soon as water vapour and salt are added, the water binds to the salt and the salt transforms into a new crystalline form. This reaction that releases heat is reversible. When heat is added to separate the water from the new crystal, the two original components are obtained again. In fact, it is this heat that is stored, and as long as these two components are separated, the stored heat is retained. This makes it a process without heat loss, which in turn is a prerequisite for long-term storage of heat. In this way a lot of heat can be stored in a small volume. Significantly more than water, and considerably more than in so-called phase transition materials.

The battery can store both heat and electricity. It has the size of a small refrigerator, expected consumer price 3,000-6,000 euro. Technical life expectancy 20 year. Storage capacity device: 200-300 MJ (600 MJ/m3). Power: 1-3 kW. The battery has 4 parts: ventilator, heat exchanger, condensor and reactor vessel:

[source]

The heat capacity is at least ten times higher than that of water and more than phase-change-based devices.

[tno.nl] – A Heat Battery For The Home: Compact, Stable, and Affordable
[tue.nl] – Miljoenensubsidie EU voor innovatieve warmtebatterij
[wikipedia.org] – Thermal battery

The European Commission has granted a 7 million euro subsidy for further development of the TNO and TUE heat battery, within the Horizon2020 framework. For that purpose a new European consortium named HEAT-INSYDE, led by TNO and TUE, will develop the heat battery for the consumer market.

[ec.europa.eu] – Horizon2020

[source] Prototype heat battery

Self-Heating Building with Algae

Renewable energy is generally associated with windturbines and solar panels. It is often ignored that electricity is only part of the entire energy story. In northern Europe for instance an average household needs to pay more for space heating than for electricity on a yearly basis. The BIQ building in Hamburg could provide the solution for an energy-neutral home that collects solar energy all year around and stores part of the solar energy in the form of algae. The algae biomass can be used for gas production and is easier and cheaper to store than warm water. Up-front capital costs are high though: $2500/m2. Reduction on fossil fuel cost to date is 33%. This number could increase if solar panels are placed on the roof, used to produce electricity to power heat pumps.

[fastcompany.com] – This Algae-Powered Building Actually Works (2014)
[doggerel.arup.com] – Tomorrow’s architecture, starring algae and hemp (2016)

Thermo-Acoustic Heat Pump

ecn-thermal-accustic-heat-pump

The Dutch national energy bureau ECN has build the prototype of a heat pump that is smaller than conventional heat pumps and potentially could become even a lot smaller. What is special about this heat pump is that it operates on sound. Sound is a pressure wave. If air is compressed it gets warmer. The ECN heat pump is a closed tube with speakers.

Core parameters: heat pump is a wall-mounted box of 40x50x10 cm. You need electricity for an air pump and speakers. Electricity of 1 kWh returns 4 kWh of heat. Air is pumped from outside and led through the (inaudible) “sound heat pump” and finally pumped into the living space, providing ventilation as an extra.

Within the Dutch context that means that you get the same heat performance from 2 kWh (40 cent) as from 1 m3 gas (64 cent). Eventually that heat pump can be powered by electricity from renewable sources. The heat pump should cost ca. $1,000 including installation.

[trouw.nl] – Warmtepomp van ECN wordt de nieuwe gevelkachel
[wikipedia.org] – Thermoacoustic heat engine

At [1:00] the sound-heat conversion is demonstrated. Sound in the tube pumps heat from lower to higher temperatures.

The thermo-acoustic principle in reverse: use heat to generate standing sound waves and create mechanical work.

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