Temperature and Humidity Stability in Harvard University Laser Labs

Background

Harvard University's specialized laser laboratories demand unwavering environmental stability for sensitive optical experiments. Powerful lasers reflect off precisely aligned mirrors on heavy stainless-steel tables, and it can take researchers weeks to align a setup perfectly. Even minor temperature or humidity fluctuations can disrupt that alignment or fog the mirrors, jeopardizing costly research and straining HVAC systems already expected to run for years. Harvard needed a targeted, cost-effective way to improve stability and extend equipment life without a full system replacement.

The Challenge

The laser labs ran on 2-ton R-22 rooftop units with heat-pipe wrap-around coils for reheat, plus a separate air handler managing return air. The systems handled 100% outside air at 300 to 700 CFM. As the coils ran wet, temperature and humidity stability suffered, making precise conditions hard to hold and shortening equipment life.

The Solution

Siemens, Harvard's service provider, worked with Rawal Devices to retrofit the existing units with the APR Control rather than replace them. Service technician Paul Podesta led the installation, focused on dehumidification and laser-table environment control. The retrofit improved performance for more than 15 years, reducing compressor cycling and system stress while keeping the labs reliable, and it performed consistently even as one unit stayed on R-22 and the other was converted to R-407C.

The Results

Since the APR Control was installed, Harvard's laser labs have held the critical temperature and humidity stability that keeps sensitive experiments running and protected. After nearly 15 years, the retrofit has:

• Protected the compressors and reduced component stress
• Contributed to long-term HVAC reliability and equipment longevity
• Cut complaints and emergency maintenance calls
• Increased facility-manager confidence in the existing infrastructure