John Song, PE

John Song is a mechanical engineer and project manager at McGuire Engineers with 10 years of experience in the HVAC industry.


Figure 7: A chilled water valve at Chicago’s Field Museum was shown to open drastically to 100%, unable to maintain the necessary discharge air temperature and operates as an on/off valve due to improper balancing. Flow through the valve and coil are improperly balanced as the system flow and pressures have changed as additional chilled water coils have been consolidated onto the central chilled water plant. Courtesy: McGuire Engineers
Plumbing, Pumping and Pumps July 25, 2023

Case study: Pressure-independent control valves will update HVAC system

The Field Museum in Chicago will incorporate pressure-independent control valves to help regulate its chilled water system

By John Song, PE
Plumbing, Pumping and Pumps July 25, 2023

Case study: Museum HVAC upgrade requires precision control

The Art Institute of Chicago incorporated pressure-independent control valves to improve energy efficiency

By John Song, PE
The differential pressure regulator within the pressure independent control valve is a key component, which consists of a diaphragm, spring and the valve. Together these components work to maintain a constant flow regardless of changes in the system pressure or load. P3 is the high-pressure side and the small capillary tube connects the high-pressure side to the bottom of the spring-controlled diaphragm. P2 shows the flow, controlled by the plug modulated by the actuator and P1 is the low-pressure side of the valve. Courtesy: IMI Hydronic Engineering
Plumbing, Pumping and Pumps July 21, 2023

Where and how to specify pressure-independent control valves in hydronics

While commercial hydronic systems are generally reliable and efficient, they can experience a range of issues that can impact performance and lead to increased energy costs and equipment failure

By John Song, PE
HVAC/R and Mechanical June 10, 2022

Applied versus packaged rooftop units — does it matter?

The line between applied and packaged rooftop units is sometimes blurred, and ultimately the needs of the project will dictate whether applied or packaged should be recommended and specified based on the wide array of available options

By John Song, PE
Case Study May 24, 2022

Case study: Theater HVAC issues resolved

A theater’s rooftop units were replaced to aid in dehumidification

By John Song, PE
Case Study April 25, 2019

Case study: Theater renovation includes VRF

A Chicago college theater renovation opted for heat recovery variable refrigerant flow systems as part of its heating and cooling plan.

By John Song, PE
Codes and Standards April 25, 2019

Don’t forget the codes

ASHRAE Standards 15 and 34 must be consulted when designing with variable refrigerant flow systems.

By John Song, PE
HVAC/R and Mechanical April 23, 2019

Choosing and specifying VRF systems

In your client’s quest for energy efficiency, determining if a variable refrigerant flow system is right requires careful consideration.

By John Song, PE
All Articles