ERV Ducted Into Dehumidifier: Fresh Air Humidity Side Effects
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- Опубліковано 12 чер 2024
- 90% of our videos these days are inspired from questions we get in our Patreon group ( / homediagnosistv)or from clients (buildingperformanceworkshop.c.... Here's a great one about the RIGHT way to sequence an ERV and a dehumidifier, if you must sequence them. But there are side effects for the system layout, control options, and other details that should be considered first.
Check out my deep dive into Ventilation Design & Installation: buildingperformanceworkshop.c...
I don't get why dehumidifier can't measure both RH and intake temperature and turn on based on these 2 parameters plus the expected room temperature. It's a simple linear equation, any basic controller can calculate this.
The issue is a control problem-on/off control and separate controls don’t work. One you need dewpoint control and a psychometric function block, which you find in a “commercial” control system, such as a CodeSys control system. So buy the commercial systems and do the programming yourself. Should take 2-3 years to tune the system.
Instead of just using rh, why wouldn't you use a temp and rh sensor to get a complete picture instead of just a partial.
I can’t tell you how many contractors connect dehumidifiers to the return side. Am I missing something? Is it not silly to dump dehumidified air into an air handler!?
Can we do a video on the optimal setup for dedicated ducted whole house humidifiers?
Why did the ventilation fan in my house suddenly stop? I set the timer for an hour, but it only worked for a few minutes and then suddenly stopped. I tried it many times and it was the same every time. What is the reason?
The ERV Manufacturers say to let their system do the bulk dehumidification work and supplement with a dehumidifier. Is that what you are saying here?
Corbett what about having an independent return from say a central hallway to the dehum , then connecting supply ie dehum exhaust , into the erv supply ducting (ie a erv skupply duct system independent of hvac ducts)
I have a ventilating dehumidifier in atlanta. It runs the fan 24/7 with a Haven IAQ controlling the Dehumidifier and dehumidifier mode on heat pump. If haven calls for dehumidification they both will run. The dehumidifier makes the temp go up and the heat pump goes cold. Haven also controls the fresh air damper. I ran the wires for an outside temp/humidity lock out but seems good thus far. If I need it I will add it. I will be installing airthings as part of a study. Guess I will see how well we did on design.
This is how we typically install ERV - DEHU systems in CZ-1& lower CZ-2. ERV supply ducted into DEHU F/A intake mixed with indoor R/A, DEHU supply ducted into AH supply. After testing different configurations we found this setup to provide the most consistent moisture control in these humid climates.
Dude, what's your background? Why are you so good at explaining this stuff AND knowing about this?
Great video. Would like to see more walkthroughs of your universal designs.
I was thinking of a similar setup a few days ago, so this video is well timed. I now understand why you don't want the dehumidifier and its controlling humidity sensor directly after the ERV since the relative humidity will change when the AHU (which I'm assuming includes the heating and cooling systems since they aren't listed separately in your diagram) increases or decreases the temperature. What I don't understand is why the dehumidifier has its own return ducting and outside air supply. Why isn't the dehumidifier just installed in the main supply duct directly after the AHU with its sensor in the duct between the AHU and the dehumidifier, similar to how the humidifier is? Having a dedicated set of return ducts going to the dehumidifier seems like a waste of resources to me, and the outdoor supply makes no sense at all, especially when there appears to be no filtration on it and you are dumping that air into the supply side of the ducting where it can't be heated or cooled to maintain the indoor temperature.
The company I use stopped making MERV 16 filters I use for my fresh air. I’d love advice on a filter box to use on the fresh air side of things. I have been looking into a hepa filter box possibly when I run out of filters. I’m just running a ventilating dehumidifier and a 10 speed fan on the fresh air side with filter box so it can be dialed in appropriately. Great video!!!
Seems a good idea in humid tropical climate. Maybe even a must.
I have a tiny house that’s built very air tight. I have an adaptive make up air system that pulls in fresh air through a filter into an “HVAC room” with a dehumidifier. It then pipes that air into the house monitoring humidity, temperature, and VPD.
What you are describing is really close to a commercial DOAS. Just an energy core or wheel followed by a mechanical cooling/heating system. Renew Air has DOAS starting at 375 CFM I think, that's not to oversized for a bigger sized house, especially with ecm fans.
My ERV (oversized core) runs continuously with exhaust from bath and fresh into my dehumidifier FA intake.
Rather than adding the additional complexity of a separate air handler and ducting for the DEHU (if you're running a mini-split system for cooling), I wonder if it wouldn't make more sense to just install one or two in-wall dehumidifiers strategically so that they can handle the load if/when the AC isn't able to.
IDEALLY, we would have a custom dehumidifier (read: small airflow) with the evaporator coil (cooling) located in the ERV fresh airstream into the house, and the condenser coil (heating) located in the stale airstream leaving the house.