Based on converting your amount into Singapore dollars (as electric tariffs are similar after conversion), amount is quite reasonable based off your total seating capacity and usage pattern.

You might consider doing refrigerant change of your 3x split units to R22a, my own experience is an average 30% drop in energy consumption of the condenser unit based on higher efficiency of R22a.

The fan coil unit (cassette) is the least of your worries; the condenser is the key. But before replacing or removing a condenser unit, be sure that the total remaining BTU capacity of the leftover 2 is able to cool down the entire restaurant at full load.

Just for an idea, turn one unit completely off during operation period and see if customers complain. If they do, DON'T remove it. You would do better by deploying a air curtain at all entrances so as to keep the cool air in.

Such a system cannot be successfully deployed within Malaysia as the fundamentals of it requires dry atmosphere; relative humidity in Malaysia is above 70%, and with such a system you would be raising the humidity to mid 90% which will cause adverse reactions (ie. rusting of metal, deteoration of wood), not to forget that the temperature does not drop as humid air retains heat, and having an air conditioner to work doubly hard to remove the heat + humidity results in negative returns; no way you will be able to achieve "more 50% electricity bill".

Additionally, swapping out an entire existing air conditioning system for an inverter based system (either VRV or VFV type systems) does not necessarily mean savings; if the entire restaurant is already running the system at near-full load, nothing can make it run lesser. Additionally, inverter systems on average deliver approximately 10 - 25% savings for small loads, and is not cumulative to "50%" as you mentioned.

This post has been edited by Nicholas Chan: Apr 1 2009, 01:05 AM

Copper losses typically is in the range of 2 - 5% for copper cables older than 10 years; there is no way you can achieve 40% savings simply by changing to thick copper cables.