Revision history [back]

Does anyone know if there are issues with the way VRF systems are modelled? And do I need to know some magic tricks to get them to work?

I'm modelling a long (about 7m W east west by 50m L north south) low set of offices set into the east facing side of a hill, with a massive glazed facade. The internal/Western offices have a full height retaining wall into the hill, and the Eastern area is an open office area of cubicles with pretty much full height glazing to north, south and east. Roof over is a concrete slab with parking.

The HVAC system is to be VRF split into North and south systems with heat recovery - i.e. simultaneous heating and cooling available.

I'm getting roughly 400 unmet occupied hours in all zones, and it doesn't seem to change anything when I change the thermostat priority settings in the VRF system. I have tried rezoning multiple ways, including just having identical areas on a single system, but this still comes out with roughly the same unmet hours. I have also done a check run with SZHP's which comes out with zero unmet hours.

Please Help!

Does anyone know if there are issues with the way VRF systems are modelled? And do I need to know some magic tricks to get them to work?

I'm modelling a long (about 7m W east west by 50m L north south) low set of offices set into the east facing side of a hill, with a massive glazed facade. The internal/Western offices have a full height retaining wall into the hill, and the Eastern area is an open office area of cubicles with pretty much full height glazing to north, south and east. Roof over is a concrete slab with parking.

The HVAC system is to be VRF split into North and south systems with heat recovery - i.e. simultaneous heating and cooling available.

I'm getting roughly 400 unmet occupied hours in all zones, and it doesn't seem to change anything when I change the thermostat priority settings in the VRF system. I have tried rezoning multiple ways, including just having identical areas on a single system, but this still comes out with roughly the same unmet hours. I have also done a check run with SZHP's which comes out with zero unmet hours.

Please Help!

Does anyone know if there are issues with the way VRF systems are modelled? And do I need to know some magic tricks to get them to work?

I'm modelling a long (about 7m W east west by 50m L north south) low set of offices set into the east facing side of a hill, with a massive glazed facade. The internal/Western offices have a full height retaining wall into the hill, and the Eastern area is an open office area of cubicles with pretty much full height glazing to north, south and east. Roof over is a concrete slab with parking.

The HVAC system is to be VRF split into North and south systems with heat recovery - i.e. simultaneous heating and cooling available.

I'm getting roughly 400 unmet occupied hours in all zones, and it doesn't seem to change anything when I change the thermostat priority settings in the VRF system. I have tried rezoning multiple ways, including just having identical areas on a single system, but this still comes out with roughly the same unmet hours. I have also done a check run with SZHP's which comes out with zero unmet hours.

Please Help! Help!

Does anyone know if there are issues with the way VRF systems are modelled? And do I need to know some magic tricks to get them to work?

I'm modelling a long (about 7m W east west by 50m L north south) low set of offices set into the east facing side of a hill, with a massive glazed facade. The internal/Western offices have a full height retaining wall into the hill, and the Eastern area is an open office area of cubicles with pretty much full height glazing to north, south and east. Roof over is a concrete slab with parking.

The HVAC system is to be VRF split into North and south systems with heat recovery - i.e. simultaneous heating and cooling available.

I'm getting roughly 400 unmet occupied hours in all zones, and it doesn't seem to change anything when I change the thermostat priority settings in the VRF system. I have tried rezoning multiple ways, including just having identical areas on a single system, but this still comes out with roughly the same unmet hours. I have also done a check run with SZHP's which comes out with zero unmet hours.

Please Help!

Does anyone know if there are issues with the way VRF systems are modelled? And do I need to know some magic tricks to get them to work?

I'm modelling a long (about 7m W east west by 50m L north south) low set of offices set into the east facing side of a hill, with a massive glazed facade. The internal/Western offices have a full height retaining wall into the hill, and the Eastern area is an open office area of cubicles with pretty much full height glazing to north, south and east. Roof over is a concrete slab with parking.

The HVAC system is to be VRF split into North and south systems with heat recovery - i.e. simultaneous heating and cooling available.

I'm getting roughly 400 unmet occupied hours in all zones, and it doesn't seem to change anything when I change the thermostat priority settings in the VRF system. I have tried rezoning multiple ways, including just having identical areas on a single system, but this still comes out with roughly the same unmet hours. I have also done a check run with SZHP's which comes out with zero unmet hours.

Please Help!