A new type of air conditioning, that combines the benefits of high efficiency heat pumps with whole-building heat recovery, has been introduced by Klima-Therm. Best known for its co-development of the Turbomiser chiller, the company has partnered with Italian manufacturer Rhoss to launch the technology in the UK
THE EXP SYSTEM (standing for excellence in polyvalent technology) is designed to optimise total energy use and heat recovery within a large building, to deliver maximum efficiency and reduced carbon emissions.

The system uses a combination of three technologies: a high efficiency reverse-cycle heat pump,an energy recovery system, and a sophisticated control platform that optimises functioning of the combined heating, cooling and domestic hot water systems to deliver the lowest possible energy usage while delivering set conditions across three modes of operation.

It can deliver cooling only, heating only and simultaneous heating and cooling throughout a multi-compartmented building, and also provide hot water for domestic use.

Robert Mallozzi, managing director of Klima-Therm, says: 'The secret of EXP's efficiency is that it harnesses energy that would otherwise be lost as waste to atmosphere via the condensers, and uses it to heat and cool the building whilst simultaneously delivering useful quantities of domestic hot water.'

He added: 'EXP effectively enables each unit of input power to deliver useful output to three areas that are normally served separately. This is coupled with the already excellent thermodynamic efficiency of a heat pump system to create a uniquely efficient system.

'In some applications, an EXP system can completely negate the need for boilers and any local burning of fossil fuel. A natural progression is to add thermal storage into the mix, and you have the ultimate system for ultra-low carbon building services.'

EXP is available in two configurations: a two-pipe system for seasonal space heating and cooling, plus all-year-round production of domestic hot water; and a four-pipe system for simultaneous or independent space cooling and heating.

Each EXP unit uses three heat exchangers. This includes a main heat exchanger for chilled water or hot water; a secondary heat exchanger for heat recovery and delivery of hot water only; and a condenser/evaporator for heat rejection and as a heat source.

The control system is built into the chiller control board, and dynamically controls and balances the energy inputs and outputs from each of these, to ensure optimum use of available energy. It also automatically minimises the number of compressor starts and stops to ensure wear and tear is reduced and the working life of the chiller plant maximised.

To verify performance EXP installations have been monitored for over extended periods, to take into account variable seasonal factors in performance and efficiency over a year, and climatic differences due to location.

An office building in Milan equipped with a four-pipe EXP system providing space cooling and heating was monitored over the course of a 12-month period. Energy use was compared with that for a similar building equipped with a traditional water chiller for air conditioning and gas powered boiler for heating and hot water.

The results showed that the EXP system cost €48,518 for energy used over the course of the year, compared with €62,282 for the traditional system - representing a 22 per cent energy reduction.

Capital costs for the EXP system are higher than for the traditional chiller/boiler solution, due to the more sophisticated technology. In the case of the above example, installation costs were €125,160 compared with €97,650 for the
conventional solution.

Despite this additional up-front cost of around €27,000, payback (taking into account the energy savings) is just over two years, after which substantial savings then accrue each year over the working life of the equipment.

Installations in cooler, more northerly climates show similar savings. A case study of a building in Stuttgart, again based on both space cooling and heating, compared the energy running costs with a similar building using a chiller and boiler.

Energy running costs for EXP came out at €52,825 compared with €74,088 for the conventional plant, representing a saving of some 29 per cent. Taking into account the higher capital costs plus energy savings, EXP had a payback of two-and-a-half years.

Even in cooler latitudes, therefore, where heat pumps are not quite as effective for all year-round operation, the hybrid system still delivers excellent performance and savings.

EXP can be used in hotels, hospitals, shopping malls, office buildings, and applications where simultaneous or independent production of chilled water and hot water is required.