Recording Studio Airconditioning Controls Strategy

[smali1]

Recording studios typically experience varying load profiles, fluctuating between partial and peak loads. When considering the implementation of fixed airflow DX package units for air conditioning within such environments, it's crucial to assess the implications, especially in scenarios where the load is at 50% and the package unit maintains a constant airflow while the compressor's cooling capacity is reduced. A technical evaluation is necessary to determine whether there's a requirement for variable speed fans and Variable Frequency Drive (VFD) operated compressors to address these dynamics effectively. This assessment involves analyzing factors such as energy efficiency, temperature control, and equipment longevity to ensure optimal performance and cost-effectiveness tailored to the specific demands of recording studio environments.
I would highly appreciate it if anyone could offer their valuable insights on this matter

 

[HVAC-Novice]

use VAV

 

[smali1]

The problem is not so simple which can be easily resolved by simply considering VAV system in DX package units

It's clear that studios experience considerable fluctuations in their cooling requirements. While a studio may need full cooling power when it's in use, such as when all lights are on, the cooling demand can drop as low as 30% during inactive periods, like when task lighting is switched off. This wide range of cooling needs presents challenges for traditional DX package systems, often causing compressors to trip and necessitating adjustments to keep coil temperatures higher. These issues typically stem from the control mechanism of DX package units, which usually regulate cooling capacity based on the return air temperature set point by cycling the compressors.

Since we're introducing raw fresh air for studio ventilation, it's crucial to consider the possibility of higher off coil temperatures when the load is reduced. Failing to properly condense moisture from the raw air can result in excess moisture being introduced into the studios. This can lead to high humidity levels and condensation problems when surfaces reach their dew point, creating significant operational hurdles.

To effectively address these concerns, I highly recommend adopting inverter-type DX package units. These units have the ability to dynamically adjust cooling capacity according to the current load conditions, ensuring optimal performance and reducing the risk of humidity-related issues.

We can maintain a fixed airflow while allowing the cooling capacity to adjust in proportion to the load.

Any suggestions on above would be highly appreciated.

 

[HVAC-Novice]

Yes an inverter-compressor or digital compressor can modulate to what you need. You may consider a separate DOAS with ERV and cooling coil do dehumidify OA. Also reset OA intake based on occupancy. the specific climate will play a role here.

I don't understand your first sentence. Are you saying VAV can't be used? VAV would benefit de-humidification during partial load. Yes, there is a limit how little flow a fan can provide. But turning down to 30% of design flow is better than keeping it at 100%. Depending on other requirements, you probably have to allow some on/off cycling of the fan during unoccupied times.

 

[smali1]

I do agree on keeping the fan at 100% rather than turning down to 30 % with VAV as such large variation in air flow may lead to the controls and operational issues and it is difficult to sent the VAVs. ON / OFF cycling of fan cannot be allowed as this project is located in gulf country where we have hot and humid conditions all the time. Fan cycling may allow the humidity level to elevate.

 

[nuuvox000]

What's the total load? If they're set on packaged RTU's for instance, you can just get a few 3 ton RTU's to break up the zones and loads. I do this all the time because packaged RTU's are just so much cheaper than other systems. They're also very simple to control and maintain which is a huge plus to some clients.

 

[HVAC-Novice]

if you don't want to modulate the fan, how do you propose to modulate cooling performance? You basically want a CV system, but that will be inherently bad at modulating and de-humidification.
Yes, big varying loads will result in varying airflow. That is what VAV does and is supposed to do.

What operational issues do you think VAV would pose? VAV is used almost everywhere without issues if done right.