[Greenbuilding] ERV Issues

[Steven Tjiang]

You want to keep the exhaust and fresh air intake runs short to minimize fan
power and preferably out of the conditioned space as they will have air of
(approx) outside temps.  If you must run them long through conditioned space
you'd want to insulate.

---- Steve (KZ6LSD)


On Thu, Nov 4, 2010 at 11:35 AM, elitalking <elitalking at rockbridge.net>wrote:

>  Thanks for your input on HRV versus ERV.  I really enjoyed the discussion
> that followed concerning the health impact of humidity.  I gained new
> knowledge from that series.
>
>
>
> Steven Tjiang <steve at tjiang.org> writes:
>
> Your analysis seem correct for your climate.  If there is no active source
> of moisture removal an ERV would only delay the inevitable equalization of
> humidity between the external and the internal.
>
>
>
> I have decided to install ERV, even though I am not immediately planning to
> install the active moisture removal to take advantage of the ERV’s ability
> to preserve that value.  I decided to preserve the option of installing
> active moisture removal such as a mini-split heat pump.  Living in a
> wooded location, with upgraded thermal efficiency from tighter and higher
> conductive insulation, I have the potential for grid tied photovoltaic array
> in field where there is full sunshine to produce the electricity credits in
> summer to pay for heat in winter.
>
>
>
> The next issue what ERV to use.  My house is small.  Using ASHRAE formula
> for required ventilation = (.01cfm/sf x Area(sf)) + 7.5cfm/occupant x
> #occupants), I only need 22cfm.
>
>
>
> Is there a source of information for comparing the performance of various
> manufacturers and models?
>
>
>
> Efficiency of recovery and reliability are important factors.  Rcomendations
> will be appreciated.
>
>
>
> I am considering
>
> * Fanteck *5504.153 *SE 704N Compact ERV
>
> * Panasonic ERV FV-04VE1
>
> * Renew air model to be determined.
>
>
>
> I spoke with an engineer recently that recommended Renew Air Energy
> Recovery Flat Plate HX.  He told me that some ERV’s with desicant wheels
> have leakage between air flows and maintenance issues caused by bearing and
> seal of wheel.  The ERV he recommended has some different method of
> transferring humidity that flows over plates.
>
>
>
> I have an L shaped 36’x26’house with long leg 10’wide and short leg
> 24’wide.  I am looking at installing HRV near north wall in area common to
> both legs so a straight 4” duct can deliver fresh air to opposite side of
> each leg.  A parallel duct on one of the legs would deliver exhaust air to
> South side for plenty of separation between inlet and outlet.  Is there a
> disadvantage for having the exhaust duct going 20’ through conditioned
> space?  Would it be advantage to have the long leg be the outdoor air
> supply instead.  I could send exhaust air out North side near inlet, but
> then continue to open end to achieve the separation needed instead of
> crossing the house.  I would like to use PVC pipe to insure tightness.
>
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