CASE STUDY: Solving Temperature Strain Behind Rooftop Pack Failures

CHALLENGE

Repeated Pack Failures, Store Closures, and Rising Site Temperatures

At Waitrose Wimbledon, the rooftop installation left two refrigeration packs exposed to high solar gain. With no shading and persistent heat stress, the units began operating outside of optimal thresholds, resulting in recurring failures and unplanned closures of the store.

The location added complexity: the packs sat within a parapet enclosure and were positioned next to an active trainline, introducing access challenges and requiring extra planning and safety considerations.

The aim was to mitigate excess heat transfer, protect system components from load-induced strain, and re-establish consistent cooling performance, while maintaining airflow and full service access.

APPROACH

Diagnosing the Problem Before Installing the Fix

To prevent further failures, the team first assessed how continuous solar exposure was affecting system performance and driving load-related faults.

Epta’s Retrofit team began by reviewing the site and analysing performance data. It became clear the packs weren’t failing due to internal defects, they were overcompensating for high ambient heat, which pushed components beyond optimal operating thresholds.

With the issue diagnosed, a site-specific solution was developed. A lightweight Unistrut frame was mounted to existing rooftop supports (no ground fixings required), maintaining a 2 m clearance around the units to preserve access and airflow. Purpose-selected shading netting, chosen for its muted and functional aesthetic, was suspended from the frame, dropping 1.5 m down each side, with raised corners to allow unhindered servicing.

This targeted intervention stabilised pack temperatures and prevented further load-induced faults.

PROJECT HIGHLIGHTS

A Technical Fix That Quietly Delivers

• Site-adapted design, working around parapet and services

• No ground penetration, anchored to existing supports

• Shading netting used to reduce solar exposure and thermal gain

• Raised corners for clear sightlines and access

• Full 2 m clearance maintained for maintenance

• Extra due diligence carried out due to nearby trainline

• No recurring failures since installation

OUTCOME

Uptime Restored And Confidence Rebuilt

Before installation, the refrigeration packs at Waitrose Wimbledon were overheating, leading to callouts, downtime, and even store closures.

Epta’s Retrofit team addressed the root cause - sustained solar exposure that was overloading the system. By stabilising the rooftop environment, pack strain was reduced and performance returned to normal operating levels.

Since the tailored fix was implemented, there have been no shutdowns at the site, consistent system performance, and meaningful operational savings as a result.

"We recently had a solar shade installed over the refrigeration packs at our Waitrose located in Wimbledon, and we couldn't be happier with the results.
The team from Epta's Retrofit department, led by Patrick Liptrott, handled everything from start to finish with professionalism and a can-do attitude.
The install was smooth and straightforward – even when small challenges came up, the team took them in stride and kept everything on track.
Since the installation, we've seen a noticeable reduction in pack load, fewer breakdowns, and less downtime – which ultimately means cost savings and more reliable service for our customers. A great experience all around!"

- Michael Platt, Oaksmere

What's Next?

Epta’s Retrofit team continues to help retailers tackle performance risks across exposed rooftop and plant installations. From heat gain and layout constraints to service access and regulatory barriers, our approach begins with diagnosis, and ends with fixes that make systems more stable, reliable, and resilient.

Get in touch with Patrick Liptrott at

Mobile: 07500 227 673

Email: patrick.liptrott@epta-uk.com