Q. What size systems make sense for Konvekta? I am working on a project where we are considering glycol run around coils for heat recovery. I would like to consider using a Konvekta system.The building in question is an existing hazardous materials storage building with 24×7 exhaust air requirements. There are 16 separate exhaust… Read more »
Posts Categorized: Ask DAC
Ask Rick: Freeze stat location?
Q: Does a freeze stat always go after preheat coil and before chilled water coil or is it OK putting it on the leaving side of chilled water coil? A: You should use a freeze stat to protect your water coils from freezing. Rooftop units with water coils should always have freeze stats, even if using… Read more »
Ask Rick: Enthalpy Wheels in Labs?
Q. I’m working on a new science building. As you have written on your web site, it’s gotten harder to use wheels. You wrote a while back about a proposed Addendum K to 62.1 – did that ever go anywhere? As you might know, the Konvekta system is proposed as an alternate, yet it seems… Read more »
Ask Rick: VAV Diffusers | R-Ring – Pressure Independence Option
Q. Is it required to add an R-Ring for every Acutherm Therma-Fuser installed? Will the R-Ring replace the return air diffuser (typically installed with regular supply air diffuser)? In what application do you need an R-Ring? Why is it an option? Is it required to add an R-Ring for every Acutherm Therma-Fuser installed? No… Read more »
Ask Rick: High Plume Dilution Fans | Control with VFD’s
Q. I have a client with 6 Strobic Air fans. They operate only 1 on a VFD with another on VFD stand-by. The other 4 run at full speed. It appears to work fine so why should all fans be needed to ramp up and down together ? Thanks A. If fans are on a… Read more »
Ask Rick: Prefilters in Front of an Energy Recovery Device?
Ask Rick: We are working on a lab application and considering not using filters on the exhaust side in front of the energy recovery device. I would like to hear the pro’s and con’s on why not to install filters. This will help us in designing future projects. I would think the efficiency would fall… Read more »
Ask Rick: Bypass Dampers on Lab Exhaust Fan Systems
Q. We are designing a lab exhaust fan system with multiple fans on a plenum. We are using Strobic Air Fans. We are using VFDs on the project. Do we need bypass dampers? A. We typically advise that bypass dampers only be used when necessary. In a lot of applications where VFDs are used, bypass… Read more »
Ask Rick: Air Handling Units | Single point power connection?
Q. We are in a disagreement over specification language. In your opinion what does a “Single Point Power Connection” include? Thanks, Boston Engineer. Good Question. This comes up all the time. Depending on the application and circumstances “Single Point Power Connection” is defined in multiple ways. Typically there are assumptions made, often times wrong,… Read more »
Ask Rick: Wrap Around Heat Pipes | What is a typical payback?
Q. What do you see as typical paybacks for Wrap Around Heat Pipes? How much does it change with geographical location? Paybacks that we are seeing with typical Wrap Around Heat Pipe applications are ranging from 2 to 4 years. Paybacks are most influenced by: percentage of cooling coil use – more use equals more… Read more »
Ask Rick: High Pressure Humidification | Direction of Nozzles?
Q. Can you confirm if the dispersion on high pressure manifolds should be into the airstream (against flow) or with the airstream? I have a question from a contractor on this and I wanted to double check with you. In the Carel humiFog system the nozzles point in the direction of airflow so they discharge… Read more »