[Equest-users] Secondary Loop Valve Type

[David Berty via Equest-users]

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@
> 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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