Innovation provider

Midroc New Technology,


Johan Siverkle
Phone: Phone: +46 10-470 70 00


Our climate innovation
Air to Air will market and develop a portfolio of Re-Hydrator products. The products will reduce energy
consumption by up to 70% and reduce the operating and maintenance cost of both new and already installed
HVAC systems.By using the physics of diffusion and steam pressure to transfer water vapor and temperature between two separate air streams, ReHydrator lowers the energy consumption in climate control systems as these now need less energy to dehumidify and cool/heat the air entering the building. ReHydrator is essentially a passive heat exchanger which uses a semi-permeable membrane rather than the metal separator found in conventional units. The materials used have been developed to maximize water vapor permeability and also have anti-bacterial properties.The technology can be used in several ways and implemented in an array of different systems. For example, ReHydrator can be used in a stand-alone fresh-air intake, in an integrated heat exchanger
in a closed system air conditioner, as a module to increase energy efficiency in passenger transportation,
and to recycle energy in industrial processes. The passive functionality allows for retrofitting
which increases the potential market. When combined with a heat pump, the product becomes an
energy efficient HVAC system.


Air to Air Sweden AB develops new energy efficient technology within the Clean Tech sector.
Air to Airs main product, ReHydrator, is a new kind of heat exchanger with a global market and great advantages compared to conventional systems.
Through its simple geometry and high efficiency it is a highly productive unit, both as an add-on application or integrated in new products. 
ReHydrator in combination with an air conditioner can increase the overall stability and efficiency of the system while still lowering maintenance costs and initial investment.

Innovative aspects (ecologic, social and economic)

Environmental  and Economic Aspects
Warm climates entail a large demand for cooling, mainly for spaces occupied by people, but also for other purposes. Improved living standards in many nations, along with rising temperatures, are rapidly increasing global use of AC. In China, where HVAC already consumes roughly 18% of the total energy supply, energy to power cooling systems is expected to increase dramatically in coming years. Measurements indicate that ReHydrator can reduce energy consumption by 50-60 % for cooling in fresh air intake space.  A standard AC system for an office or apartment has a cooling capacity of 3.5 kW, comparable to 1kW electric capacity (energy consumed). Saving 50% means saving 0.5 kW or 2 kWh/day, if the unit runs 4 hours per day. Over the course of an entire year, this amounts to 730 kWh. Every year 63 million AC units are sold globally.If 25% of these were to employ ReHydrator technology, the energy consumption would be cut by 5.7 TWh. After five years, the annual savings would be 28.5 TWh or 28 million tons carbon dioxide.

Social Aspects (related to the work conditions)
A better indoor climate is very important for the health

Economic Aspects
See above

Application examples

The future
How will ReHydrator reach the global market? Our concept is based on partnerships and joint ventures with multinational corporations with established lines of production, distribution, and sales. We will target several market sectors in the development of our marketing strategy, since the product can be used within an assortment of applications.
Through collaborations with these large corporations, the product can quickly access separate markets and expand globally.
Expansion /export strategy.
We are focusing on tropical climate markets in Asia and Australia, primarily in applications where Re-Hydrator can work as an integrated part of an AC unit



Current stage of development

Entering the market 

Intellectual Property Rights

Patent granted

Country of origin


Country of application



National Contact Point

Uwe Fortkamp
IVL Svenska Miljöinstitutet AB
Valhallavägen 81
P.O. Box 210 60
114 27 Stockholm

Tel: +46 8 598 56300
Tel: +46 8 598 56390