SolarICE: new off-grid cooling technology

Sustainable heating and cooling systems
21 September 2020

In developing countries there is a huge need for cooling systems, that are affordable and operate off-grid. Think about cooling vegetables and fruits directly after harvesting, cooling milk during transport to collection centers and cooling buildings. TNO developed SolarICE: a smart, economical and clean cooling system that operates independently from electricity networks. We are looking for companies who can launch this technology in the market.

SolarICE technology


This environmentally friendly cooling method is based on salt, being endothermically hydrated by dissolution or in water. In order to dissolve, the salts requires energy in the form of heat that can be extracted from the environment. This behavior, can be used as cooling mechanism for products such as food, medicines and milk, or in buildings.

These types of salt can provide cooling effects of up to 200 KJ/kg salt when dissolved in water. In systems and methods that utilize endothermic salts, it is desired that the endothermic salt is regenerated after the cooling is exhausted. This allows the recycling of the salts and reduces the requirement to replenish the system with fresh endothermic salts.


Energy is needed to support salt regeneration. However, in areas with abundant solar irradiation, the thermal heating can easily be substituted by renewable alternatives. The experimental data shows, that solar activity in India is sufficient to regenerate the salt in 4 hours, without any additional measures. The regeneration allows for reducing losses and cost in operating the system.

Robust and affordable

The system can be manufactured from local materials. Depending on the scale and application of use, SolarICE products can have a pay-back period between 8 and 28 months. At the moment SolarICE is the cheapest method of generating cold in off grid location. The system is easily scalable, modular, affordable and can run on renewable energy sources, without access to electrical grid. Moreover, the absence of vacuum parts, make it simple and reliable. It can be built for both - manual and (semi)automatic mode of operation.

The technology is invented and patented by TNO. Last year a demonstrator of SolarICE was built and the performance was tested in the lab. The prototype of the SolarICE cooler has been designed by TNO and produced in close collaboration with Van Berlo Ltd. The results of our techno-economic evaluation as well as lab measurements are promising and can be shared with interested parties.


Because of the simplicity of design and operation as well as scalability, SolarICE can be used for a range of applications:

  • Cooling dairy, vegetables and fruits at farms or at village level in cold storages
  • Cooling medicines in hospitals and health centers
  • Airconditioning for houses: to lower the indoor temperatures

As an example, with related to dairy supply chain, the most vulnerable stage, where the lion share of 20% losses occur, is the phase between milking cows and product delivery at the village collection point. Saving merely 1% of those losses by sufficient cold storage, would yield additional 800.000 ton of milk products (!) reaching consumers alone.

Potential impact

Needless to say, that proper cooling of dairy, fruits and vegetables will result in higher quality of food, lowered post-harvest losses, increased income for farmers and improved access to affordable nutritious food to people in the region. All very important socio-economic impacts at most vulnerable families, who still struggle in the remote areas, with no access to electricity of natural gas. For those communities, setting up an off-grid, affordable, cooling solutions, like the one based on SolarICE principle, might be make-or-break situation.


We are looking for companies who are interested to launch SolarICE in cooperation with TNO and other relevant partners. We are eager to turn this technical idea into socially and commercially viable opportunity. Contact Piotr Pukala for more information.

This TNO project supports the following sustainable development goal

Affordable and Clean Energy