For a mixed-use building, we would like to see the savings through installing a variable refrigerant flow system in eQuest. Anybody has any experience with this? Does eQuest actually support VRF systems?
This is a great question Omer. Here, variable refrigerant flow (VRF) systems
are new and I understand they are ubiquitous in Asia and growing in Europe
(and it looks like you are between the two!). There is one software company
here, EnergyPro, which has capacity to model VRF systems but also has a few
shortcomings. It would be extraordinarily beneficial if eQuest could perform
this function.
Does anyone have any comments or "how-to" advice and/or can this item be
placed on the eQuest wish list?
I replied to Omer's post this morning. I'll repost it to the entire
group below:
Omer,
I have successfully modeled a VRV system (aka VRF) in eQuest, so long as
it is the variety that does not simultaneously heat and cool. I have
made several posts about it. Just search for my name with VRV in the
archives and you should be able to find it. Due to workload, I
unfortunately do not have the time to help you any further than that for
now.
It's ok Jeff... I'm in the office this late anyways, what's another 5
minutes?
Not all VRV/VRF systems simultaneously heat and cool, and regardless of
which one you end up with, both are very efficient.
Most of the simultaneous systems we have found to be not-so
cost-effective for our clients. That isn't to say we haven't utilized
them before, but, more often, we go with the non-simultaneous kind
because of the same superior efficiencies and lower first-cost.
With the systems that do not simultaneously heat and cool, very high
efficiencies are still obtained due to the fact that the compressor is
only using as much energy as the system needs to remove heat from one
place to the other. This compressor speed change occurs while the
evaporator and condenser remain the same size. In the old days, If you
wanted to increase the efficiency of a refrigeration system, you
increased the size of your condenser and evaporator. With VRV, you keep
the evaporator and condenser the same size, just shrink the load you put
on them. Therein lies the true genius of VRV: the varying capacity.
Your statement is true about utilizing the diversity of loads to
maximize efficiency, and if you have that load diversity, you will
probably find better payback and the extra expense of the system will
probably become much less of an issue. Most of my clients are K-12
schools, and there isn't a lot of core areas, at least in older
buildings. Considering that most of my building is heating in the winter
with little to no areas requiring cooling, simultaneous heating and
cooling doesn't do me very well, hence the reason why I haven't spent
time figuring out how to make it work.
As with all things HVAC: It depends on your application.
This is a great question Omer. Here, variable refrigerant flow (VRF) systems
are new and I understand they are ubiquitous in Asia and growing in Europe
(and it looks like you are between the two!). There is one software company
here, EnergyPro, which has capacity to model VRF systems but also has a few
shortcomings. It would be extraordinarily beneficial if eQuest could perform
this function.
Does anyone have any comments or "how-to" advice and/or can this item be
placed on the eQuest wish list?
Regards,
Jeffrey G Ross-Bain, PE, LEED
Jeff, et al.,
I replied to Omer's post this morning. I'll repost it to the entire
group below:
Omer,
I have successfully modeled a VRV system (aka VRF) in eQuest, so long as
it is the variety that does not simultaneously heat and cool. I have
made several posts about it. Just search for my name with VRV in the
archives and you should be able to find it. Due to workload, I
unfortunately do not have the time to help you any further than that for
now.
Thanks,
Gary Schrader
It's ok Jeff... I'm in the office this late anyways, what's another 5
minutes?
Not all VRV/VRF systems simultaneously heat and cool, and regardless of
which one you end up with, both are very efficient.
Most of the simultaneous systems we have found to be not-so
cost-effective for our clients. That isn't to say we haven't utilized
them before, but, more often, we go with the non-simultaneous kind
because of the same superior efficiencies and lower first-cost.
With the systems that do not simultaneously heat and cool, very high
efficiencies are still obtained due to the fact that the compressor is
only using as much energy as the system needs to remove heat from one
place to the other. This compressor speed change occurs while the
evaporator and condenser remain the same size. In the old days, If you
wanted to increase the efficiency of a refrigeration system, you
increased the size of your condenser and evaporator. With VRV, you keep
the evaporator and condenser the same size, just shrink the load you put
on them. Therein lies the true genius of VRV: the varying capacity.
Your statement is true about utilizing the diversity of loads to
maximize efficiency, and if you have that load diversity, you will
probably find better payback and the extra expense of the system will
probably become much less of an issue. Most of my clients are K-12
schools, and there isn't a lot of core areas, at least in older
buildings. Considering that most of my building is heating in the winter
with little to no areas requiring cooling, simultaneous heating and
cooling doesn't do me very well, hence the reason why I haven't spent
time figuring out how to make it work.
As with all things HVAC: It depends on your application.
Good luck,
Gary Schrader