[Equest-users] Secondary Loop Valve Type

[Darryl Kasun via Equest-users]

Great - that makes sense to me - thanks for you help David!

On Tue, Aug 23, 2016 at 2:54 PM, David Berty <
dberty at baselineenergyconsulting.com> wrote:

> Oh OK, I'm catching what you're pitching now.
> I would enter that as a three way valve with no head loss as you suggested.
>
> Anybody else done something different with this?
>
> David Berty, P.E.
> Baseline Energy Consulting
> 317.220.9272
>
> On Aug 23, 2016 5:46 PM, "Darryl Kasun" <darryl.kasun at gmail.com> wrote:
>
>> Yup absolutely.  But there's no real valve at the primary/secondary
>> connection - just a tee.
>>
>> On Tue, Aug 23, 2016 at 2:44 PM, David Berty <
>> dberty at baselineenergyconsulting.com> wrote:
>>
>>> Sounds to me like you have a three way valve at the primary-secondary
>>> interface. You said that the primary was constant, that most likely means a
>>> three way valve to ensure that primary pumps never vary in flow. What
>>> doesn't go to the secondary loop will return to the chiller. Does that make
>>> sense in your project design?
>>>
>>> David Berty, P.E.
>>> Baseline Energy Consulting
>>> 317.220.9272
>>>
>>> On Aug 23, 2016 5:35 PM, "Darryl Kasun" <darryl.kasun at gmail.com> wrote:
>>>
>>>> Hi David,
>>>>
>>>> The flow in the secondary loop definitely varies based on differential
>>>> pressure setpoints.  There are two way valves at reheat coils, reflected
>>>> ceiling plans, etc.  And I've entered this input (two-way valve) at the
>>>> thermal zone level.
>>>>
>>>> I guess I'm confused at the circulation loop level.  In this window,
>>>> there is also an "valve type" input for the secondary loop.  I know the
>>>> primary loop is constant and the secondary loop is variable so I'm thinking
>>>> this input should be "two-way valve" again.  These two inputs seem
>>>> redundant to me...
>>>>
>>>> On Tue, Aug 23, 2016 at 2:12 PM, David Berty <
>>>> dberty at baselineenergyconsulting.com> wrote:
>>>>
>>>>> Darryl,
>>>>> A three-way valve will maintain constant total branch or loop flow by
>>>>> modulating the flow to either the coil or directly to the return line. A
>>>>> two-way valve will modulate open or closed to maintain a flow or
>>>>> temperature (usually leaving air temp), as it closes it will reduce the
>>>>> total loop or branch flow proportionally. 3 way valves are not generally an
>>>>> acceptable choice because they run counter to the desire to reduce flow to
>>>>> reduce energy consumption. These valves are usually at the coil but can be
>>>>> at the primary secondary interface they perform the same function in
>>>>> general at either location. Smaller systems that might lack sufficient
>>>>> diversity to ensure a minimum level of system flow sometimes use these
>>>>> valves to ensure that the pumps don't "dead-head".
>>>>>
>>>>> David Berty, P.E.
>>>>> Baseline Energy Consulting
>>>>> 317.220.9272
>>>>>
>>>>> On Aug 23, 2016 2:17 PM, "Darryl Kasun via Equest-users" <
>>>>> equest-users at lists.onebuilding.org> wrote:
>>>>>
>>>>>> Hi eQUESTers,
>>>>>>
>>>>>> For a secondary loop, there is an input for valve type - either three
>>>>>> way or two way.  Can anyone provide a schematic or quick explanation of the
>>>>>> difference between how these two valves control the flow from the primary?
>>>>>> Is this input assuming there is a valve at the secondary loop connection?
>>>>>> If there is a simply a tee at the secondary connection, can the valve head
>>>>>> input be zero?
>>>>>>
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>>>>
>>
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