User guide

3 - Creating a Daikin VRV System
Page 14
Daikin VRV Systems Plugin
VE2012 User Guide
Simulation Results
It is possible to obtain efficiencies in excess of the published figures with this module, very high or
low efficiencies are also possible but can be symptomatic of Apache system or profile anomalies.
Care should be taken to check the following before updating the simulated results to the model (The
simulated results can be automatically assigned to the Apache systems in the relevant efficiency
fields, which is performed when exiting the VRV systems module)
Very high efficiencies (typically exceeding 9)
Check your heating and cooling setpoints are correct, if at any point the cooling setpoint is lower than
the heating setpoint then artificially high efficiencies will result.
Check that simultaneous heating and cooling is occurring, High efficiencies usually come from
designs where heat recovery is optimised.
Check your simulated loads do not exceed the capacity of the loads run. A warning will appear if this
occurs at the end of the simulation, this can sometimes produce very efficient results even though the
system is not producing enough capacity to satisfy the room design load.
Very low efficiencies (around 3 or below)
System low efficiencies are usually indicative that the system requires re-selection. A number of
considerations should be taken into account to alleviate the chances of inefficient system design
which are listed below.
In Vista, look for points where the VRV system (not individual zones) is supplying small loads of a few
hundred Watts or less, due to minimum operating loads VRV systems are less efficient at this point
and can reduce total simulated efficiency.
In air tight buildings, low heating and cooling loads can be produced. In order to maximise the
efficiency of the VRV system it’s possible to identify zones or rooms that require simultaneous
heating and cooling. Placing these zones onto the same system will significantly increase the
efficiency of the VRV system by use of the heat recovery effect.