air handler question

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
A VFD is a good electrical solution to an identified mechanical problem if properly applied. But as electricians, we are not qualified to properly identify the mechanical problem and vet the solutions. Mention it, but turn it over to an HVAC specialist.
 

Ingenieur

Senior Member
Location
Earth
Most units have adjustable sheaves to adjust airflow

without the unit specs, control diagram and P&ID of the unit hard to comment

it usually comes down to the controls
 

Sahib

Senior Member
Location
India
A VFD is a good electrical solution to an identified mechanical problem if properly applied. But as electricians, we are not qualified to properly identify the mechanical problem and vet the solutions. Mention it, but turn it over to an HVAC specialist.
In other words, to enable the OP to have an intelligent discussion with HVAC specialists.
 

Sahib

Senior Member
Location
India
That appears to be about modifying a chiller system. I don't think we are talking about a chiller.
The article discusses about retrofitting of various components of an HVAC system. Particularly the following para from the article addresses iwire objection.

Traditionally, VSDs were viable only if the systemwas designed as a VAV (variable air volume) system(see Air Handling Unit section). However, advancesin control algorithms allow you to implement a VSDin any type of air conditioning system. Depending onthe control algorithm and the humidity requirementsin the space, the anticipated energy saved can reach45 per cent of the fan energy.
 

iwire

Moderator
Staff member
Location
Massachusetts
The article discusses about retrofitting of various components of an HVAC system. Particularly the following para from the article addresses iwire objection.
:lol:

Its a sales paper, of course they say it can be easily implemented in any equipment.

The fact is, it wont be implemented in a typical restaurant RTU.
 

Mgraw

Senior Member
How are you sure about it?
I am sure. You would need to modify the entire system. You can not just modify the airflow. The evaporator coil and the condenser coil would need to be modified. The compressor would need to be replaced with one that is designed for variable speed. The condenser fans would also need to be controlled. It would be cheaper to replace the unit with one that has those features already built in.
 

Sahib

Senior Member
Location
India
The OP's problem is noise from air flow. By installing a VSD for the blower motor, the air flow and so noise could be reduced consistent with the heat load, also bringing about energy saving. It is a part of conversion process of constant volume air conditioning system to variable volume air conditioning system. 100% energy saving due to above conversion may be realised by more exhaustive retrofitting as discussed.

Armed with above such knowledge, the OP may approach a HVAC specialist for his problem now.:)
 

iwire

Moderator
Staff member
Location
Massachusetts
The OP's problem is noise from air flow. By installing a VSD for the blower motor, the air flow and so noise could be reduced consistent with the heat load, also bringing about energy saving. It is a part of conversion process of constant volume air conditioning system to variable volume air conditioning system. 100% energy saving due to above conversion may be realised by more exhaustive retrofitting as discussed.

Armed with above such knowledge, the OP may approach a HVAC specialist for his problem now.:)
:lol:

I love the comedy you bring to the forum.
 

Mgraw

Senior Member
The OP's problem is noise from air flow. By installing a VSD for the blower motor, the air flow and so noise could be reduced consistent with the heat load, also bringing about energy saving. It is a part of conversion process of constant volume air conditioning system to variable volume air conditioning system. 100% energy saving due to above conversion may be realised by more exhaustive retrofitting as discussed.

Armed with above such knowledge, the OP may approach a HVAC specialist for his problem now.:)
The OP's problem is the velocity of air and short run times. Adding a VFD alone is not a solution.

BTW I am a HVAC contractor and an electrician.
 

mgookin

Senior Member
Location
Fort Myers, FL
The OP's problem is noise from air flow. By installing a VSD for the blower motor, the air flow and so noise could be reduced consistent with the heat load, also bringing about energy saving. It is a part of conversion process of constant volume air conditioning system to variable volume air conditioning system. 100% energy saving due to above conversion may be realised by more exhaustive retrofitting as discussed.

Armed with above such knowledge, the OP may approach a HVAC specialist for his problem now.:)
Really? It says too hot and too cold.


A friend has a restaurant where he had a roof ac / heater unit installed and much to large for the area. The air flow is too much for anyone to put up with. It gets too cold or hot too quick. You can not sit anywhere near [under] the air flow. Money is a concern for him. Would a speed control like a vfd be a possible solution for this problem.

If some one has another means [idea] we would love to hear it. Replacing unit is not an option, its 2-3 years old and expensive.
I don't see the word noise.
 

electricman2

Senior Member
Location
North Carolina
Occupation
Electrician
Guys, if we had an HVAC contractor recommending modifications to an electrical system we would all be shouting unqualified yet you all feel qualified to recommend modifications to an HVAC system.


It makes no sense. :happysad:
After 4 pages this is still the best reply. I have had customers ask for help with A/C or heat problems. I tell them I'm an electrician, they need to see a HVAC tech.
 

topgone

Senior Member
After 4 pages this is still the best reply. I have had customers ask for help with A/C or heat problems. I tell them I'm an electrician, they need to see a HVAC tech.
That's partly true. But as electricians, people get to rub elbows with HVAC techs. HVAC techs refer to us on electrical matters and sometimes go beyond electrical things and teach electricians about things HVAC techs do.

FYI, this problem is no surprise to me. This happens all the time; mismatches of equipment versus actual conditions. The good thing is, the HVAC equipment installed is bigger than the requirement, hence it can be tweaked to suit the application.
 

iwire

Moderator
Staff member
Location
Massachusetts
That's partly true. But as electricians, people get to rub elbows with HVAC techs. HVAC techs refer to us on electrical matters and sometimes go beyond electrical things and teach electricians about things HVAC techs do.
Rubbing elbows with another trade does not make us quilified to do that trade.

Regardless of our superhero electrical credentials. :)
 

topgone

Senior Member
Rubbing elbows with another trade does not make us quilified to do that trade.

Regardless of our superhero electrical credentials. :)
Nobody claimed they're "qualified", that's for sure! People learn by asking others, and that's probably the biggest reason why Mike put up this forum. One came with a question, and we tell the guy there's a solution. How he does it, it's his thing. Pray, tell me that ain't so?
 
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