Air conditioning Multiplex replaced its ammonia machines system.
The CGR City cinema in Newcastle has found new life. Modernized and enlarged – it now has 12 rooms and occupies 5,500 m² – the multiplex has also transformed its air conditioning and heating system. In summer, the temperature could reach up to 38 ° C.
The old device, a set of 21 absorption machines running on ammonia, combined the disadvantages: “Not only are handling of this fluid dangerous, but spare parts are difficult to find”, explains, director of the installation company Concept. Aggravating factor, the maximum power of the general low voltage switchboard was reached. To increase its capacities, it would have been necessary to “set up a transformer with a higher capacity, which would have entailed an additional cost of 100,000 euros on the overall invoice for the works,” he continues.
In order to conserve available electrical power while improving the efficiency of the equipment, the company proposed using town gas to supply seven air conditioning systems with variable refrigerant flow, known as “DRV”. These were devices from the Eco G 2-tube range from the manufacturer Panasonic, which were chosen. Operating with R 410 A refrigerant and installed on the roof, they have a unit power of 85 kW in cold and 95 kW in heat. One of the groups operates in direct relaxation and supplies the entrance hall and its 9 m of free height. It is connected to six ducted units hidden in the ceilings.
“Each device ensures a variable air flow of between 23 and 34 m3 / minute with a static pressure adjustable between 10 and 150 Pa”, explains Boris Comte, technical sales representative at Panasonic.
Energy savings. The other six DRV groups provide air conditioning and heating for eight of the 12 cinemas, via the dual-flow air handling units (CTA) already in place. “The coupling of DRVs to CTAs relies on a remote hydraulic module, and therefore a water network. The latter is stored in a mixing flask with a capacity of 1,500 l with high thermal inertia. Thanks to this cold reserve, power calls to DRVs are limited, which saves energy, ”explains Christophe Muel. In detail, two RVDs can be connected to three CTAs. “This cascade operation also has the advantage of limiting the stresses on the machine in the short cycle and thus avoiding overconsumption and premature wear”, points out Boris Comte. Thanks to this original installation,
The installation of these devices and the water network was to be carried out without interruption of operation. To meet this requirement of the client, the installer has anticipated the seasons. “We started by installing the four 120 kW condensing boilers powered by city natural gas in the summer of 2017, so that they are ready for heating. The following winter, we worked on the refrigeration system, ”explains Christophe Muel. The old water networks were replaced, before the installation of the RVDs and the hydraulic modules. Once the installation of the systems was finalized, the teams dismantled the old ammonia machines piece by piece.
The works, whose overall budget amounts to 450,000 euros before tax, were completed in October 2018. A little more than a year later, maintenance is simplified since the number of machines has halved. Maintenance every four years is necessary as well as an annual check when the are restarted. As for gas consumption, the new system saves 20% in winter.0