[Equest-users] Secondary Loop Valve Type

[Darryl Kasun via Equest-users]

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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