Opus Project

The Challenge

Opus International Consultants is a leading international engineering consultancy.  To ensure their Christchurch office would showcase the very best air-conditioning technology, they needed a system that would combine stellar performance with outstanding energy efficiency. With weather ranging from the oppressive heat of the infamous nor’wester to the biting cold of winter southerlies, heating and cooling power would be equally important.  The heavily-insulated and draft-free office required a powerful ventilation system to maintain a healthy work environment. But the outside air temperature would seldom suit the office environment. Fresh air would have to be heated or cooled before it could be pumped inside.

Noise posed another challenge. The Moorhouse Avenue location offers a pleasant view of Hagley Park, but it is one of Christchurch’s busiest thoroughfares. Opus required a ventilation system that would not bring traffic noise into the office.

Because it has large sun-trapping windows and dark interior corners, there would be times when some parts of the office needed heating while others required cooling. To maximiseenergy efficiency, it would be essential that the new air-conditioning system could transfer heat from warm zones to cool ones.

The Solution

Opus selected a Mitsubishi Electric City Multi System, and a ventilation system featuring a Mitsubishi Electric Lossnay Fresh Air Heat Recovery System.  Thanks to effective filtering and the Lossnay’s heat exchanger, the new ventilation system brings nothing but fresh air into the office. Dust and heat stay wherethey belong and the Lossnay core eeduces noise levels by 50%.

When it’s cold outside, the Lossnay transfers heat fromwarm exhaust air to the cold, incoming fresh air. When it’s hot outside, the Lossnay cools incoming fresh air by transferring its heat to the outgoing stale air.  With a temperature recovery efficiency of up to 82%, the Lossnay minimises the air-conditioning system’s workload.

 To condition incoming air, the air conditioner only has to make up for the small amount of energy that the Lossnay doesn’t recover from the exhaust.  Because the office is heavily insulated, and because itsventilation system eliminates unnecessary heat loss, the office needs a relatively small air-conditioning system.  But to achieve benchmark energy efficiency, Opus wanted a highly efficient system. With its heat recovery technology and its excellent coefficient of performance, City Multi was the logical choice.

Able to rapidly and silently change between heating and cooling modes, it easily handles Christchurch’s changeable weather. Mitsubishi Electric’s heat recovery technology requires a minimum of energy to transfer heat between warm and cool zones, eliminating unnecessary
waste.  To get the most out of their efficient air-conditioning and ventilation system, Opus International  Consultants chose a web-based controller. With central control of all system parameters, the building manager can fine-tune the system for maximum performance.