New approach for energy-efficient buildings

While today most of the energy consumed is spent on heating, large sums can be saved by enhancing the energy efficiency of HVAC systems. With EU funding of the project 'Energy efficient heat exchangers for HVAC applications' (ENE-HVAC), researchers are developing new technologies to reduce their energy consumption.


ENE-HVAC will use nanotechnological coatings and surface treatments to improve heat transfer, as well as new nano- and micro-materials to improve refrigerant efficiency. New nanotechnological additives will enhance the coolant efficiency and heat transfer capabilities.


The project's ambitious goals can be realised only by tackling efficiencies in all parts of the HVAC system. The project deals with heat exchanger efficiency on both the air and liquid sides of heat exchangers such as condensers/evaporators and on heat recovery systems. It also addresses the heat transport system to ensure high efficiency throughout the HVAC system. To minimise harmful effect on the climate, ENE-HVAC is using natural refrigerants such as carbon dioxide and ammonia instead of chlorofluorocarbons and hydrofluorocarbons.


Nanotechnological coatings will be applied on the air side of both air-to-air and liquid-to-air heat exchangers. In particular, sol-gel coatings are being developed and characterised that should significantly decrease ice formation and adhesion to heat exchanger fins. Based on these, the de-icing cycles can be minimised or completely avoided, thus allowing significant energy savings.


On the refrigerant side of the liquid-to-air and liquid-to-liquid heat exchangers, researchers are working on micro- and nano-structured surfaces to achieve large increases in refrigerant boiling efficiencies. Such activities are aimed at decreasing the heat exchanger's energy usage.


Furthermore, researchers are manipulating surface polarity of the under-development sol-gel coatings to improve heat transfer capabilities of both refrigerant and brine. Use of single-digit nanodiamonds is expected to significantly increase natural refrigerant efficiencies.


ENE-HVAC innovative technologies will contribute to slashing total energy use by 50 % compared to those used in conventional commercially available systems. Project achievements should provide the European industry with a competitive advantage in the field of energy-saving technologies.