[4] The adsorbent is a solid, such as silica gel, activated carbon, or zeolite.
[2] Adsorption refrigeration has been extensively researched in recent years because the technology is often noiseless, non-corrosive and environmentally friendly.
[5] The heat source for adsorption refrigeration can be fossil fuel, biomass fuel, nuclear fission, geothermal energy, waste heat, or solar thermal energy.
[1] Adsorption refrigerators are available in the marketplace and are mainly used to produce chilled water from waste heat.
Gas adsorption heat pumps are not currently available in the UK, but are just being introduced in Europe as small water or ground source packaged units that provide domestic, low-temperature space heating.