METRO Cash & Carry, Ravi Road Lahore — retail cold storage with 595-tonne absorption chiller HVAC and PIR walk-in cold rooms

A large-format Cash & Carry is not one refrigeration problem — it is three separate and distinct problems that must be solved in the same building without interfering with each other. The first is the HoReCa trading floor: a large open space with high occupancy, intense lighting, and a 45°C Lahore summer pressing on the exterior envelope. The second is the display refrigeration: open-deck dairy cases, glass-door frozen reach-ins, and chilled deli counters that must maintain product temperature while being accessible to members all day. The third is the back-of-house: walk-in cold rooms where produce is prepared, meat is portioned, and dairy buffer stock is held in advance of replenishment.

METRO AG's plant standard for its Pakistan operations specified a central chiller approach for the trading floor — and unusual for Pakistani retail, a lithium bromide absorption chiller as the primary cooling plant. Izhar Foster was the engineering partner for cold room construction, insulated door supply, and the full HVAC ductwork installation from the chiller to the trading floor. This is one of the most complex single-site refrigeration and HVAC integrations Izhar Foster has delivered in Pakistan's retail sector.

The absorption chiller — what it is and why it matters in Pakistan

A 595-tonne refrigeration capacity is a large number for a single chiller serving one retail store. To understand why it is sized at this level, consider what the METRO Ravi Road trading floor is: a high-bay space with a ceiling at 8–10 metres, heavily loaded with member traffic, lit to METRO's specification, and built with walls and roof that face 45°C Lahore ambient in summer. The sensible cooling load on a floor of this size in this climate can reach 400–600 tonnes — which is exactly where the 595-tonne machine sits. It is not oversized; it is sized for what the building actually demands.

The choice of lithium bromide absorption technology is the engineering decision that sets this project apart. A conventional vapour-compression chiller — a centrifugal or screw-based electric machine — needs electricity to run its compressor. In Lahore, LESCO load-shedding during summer peaks can remove grid power for 4–8 hours per day in industrial and commercial zones. When a conventional chiller loses power, it stops. The trading floor temperature rises. Products warm. The 8-metre ceiling retains heat, and recovery when power returns can take 45–60 minutes. For a METRO store that operates a continuous trading day and cannot remove members from the floor during a power cut, this is an operational and reputational problem.

An absorption chiller has a different energy source: it runs on gas, not electricity. The LiBr-water cycle — where lithium bromide solution absorbs water vapour at low pressure (acting as refrigerant), is then heated in a gas-fired generator to release the water vapour at high pressure, which condenses to provide cooling — requires only pump electricity, which is a fraction of the compressor load. A 595-tonne absorption chiller can be maintained in operation on a small UPS or genset during a grid outage, continuing to cool the trading floor while the electrical supply is interrupted. In Pakistan's load-shedding reality, this is the difference between a store that stays open and one that closes.

Dual-system design — central chiller for HVAC, DX rack for refrigeration

The 595-tonne absorption chiller serves only the trading-floor HVAC. Chilled water from the chiller is pumped to air handling units distributed across the trading floor; the AHUs condition the air and deliver it through the ductwork Izhar Foster installed. This chilled-water system is designed for comfort cooling — maintaining a trading floor at approximately 22–24°C — not for product refrigeration temperatures.

Product refrigeration is served by a separate and independent DX (direct-expansion) refrigeration rack. The two systems are deliberately independent because their operating requirements are incompatible. A comfort-cooling chilled-water system runs chilled water at +7/+12°C supply and return — fine for an AHU coil, useless for a display case that needs −8°C evaporating temperature. A DX rack for display cases runs at low suction pressure, cycles defrost, and manages the variable load of open-deck cases with their high infiltration as members browse. The two systems share the plant room and the electrical distribution but operate as separate refrigeration cycles.

The DX rack serves three types of display equipment:

• Open-deck dairy and deli cases (+2/+4°C). These are the most common display fixtures in a Cash & Carry — multi-deck open cases accessible from the front, with air curtains providing a partial thermal barrier. In Lahore's ambient, the heat infiltration into an open case is significantly higher than the European design figure; Izhar Foster's rack sizing accounts for Pakistan-specific infiltration loads using ASHRAE Refrigeration Handbook Ch. 24 methodology rather than European published rack load tables, which can underestimate Pakistani ambient by 15–20%.
• Glass-door frozen reach-ins (−18°C). Frozen food display cases with glass doors that close between member selections. These have substantially lower infiltration load than open cases, but at −18°C the coil temperature is −25 to −28°C, placing these cases on the low-temperature suction of the rack. Defrost cycles on frozen cases must be managed carefully in a retail environment — product temperature excursions during defrost are visible to members and can trigger complaints.
• Back-of-house walk-in chiller interface. The back-of-house cold rooms are connected to the DX rack via a dedicated evaporator circuit, with temperature independent of the display-case circuit. This allows the walk-in rooms to be locked and held at setpoint overnight without cycling with the display cases, which may defrost or have their setpoints adjusted during off-hours.

Back-of-house walk-in cold rooms — PIR construction and food hygiene

The back-of-house cold rooms at METRO Ravi Road serve the functions that make a large-format Cash & Carry operationally viable: fresh produce washing and repacking, meat and poultry portioning, and dairy buffer stock management. These are not simple cold rooms — they are food preparation environments that must meet METRO AG's global food safety standards alongside Pakistani food hygiene regulations.

The construction specification for back-of-house food-prep cold rooms differs from a straightforward storage cold store in several important ways:

Wall and ceiling surfaces. FireSafe PIR panels with pre-painted steel internal faces are non-porous, non-hygroscopic, and cleanable with pressure washdown. The pre-painted finish is food-safe and does not absorb odours or moisture. Every wall-floor junction is coved with a continuous PIR or stainless-steel cove fillet — no right-angle junction that cannot be cleaned. Drains are located at the lowest point of the floor, which has a minimum 1:80 fall toward the drain channel.

Temperature zoning within the back-of-house. Produce preparation (+4°C) and meat preparation (+2°C) are separate rooms, not zones within the same room. Cross-contamination between produce and raw meat is a food-safety failure that costs METRO its audit certifications. Separate rooms with separate doors, separate air circulation, and separate drainage are the engineering answer.

Door specification. Insulated cold-store doors at the back-of-house interface are high-cycle — a busy Cash & Carry back-of-house opens and closes its cold-room doors hundreds of times per shift. Izhar Foster's insulated doors for the METRO Ravi Road back-of-house were specified with high-cycle hardware (100,000-cycle hinge and cam ratings), multi-stage perimeter gaskets with field-replaceable seals, heated frames where the door meets ambient air (preventing condensation and ice build-up on the door frame that would impede closure), and anti-panic opening from inside (for staff safety in the cold room environment).

Full HVAC ductwork scope — trading floor distribution

The 595-tonne absorption chiller produces chilled water, but chilled water is only useful if it reaches the members on the trading floor. Izhar Foster installed the full AHU duct distribution system across the METRO Ravi Road trading floor — from the chilled-water AHUs in the plant area, through supply and return ductwork coordinated with the store's structural grid and racking layout, to diffusers positioned to give uniform temperature distribution on the floor without cold spots at the checkout area or hot zones in the frozen food aisle where display-case heat rejection competes with HVAC supply.

Ductwork design for a high-bay retail space requires careful CFD or zonal modelling to avoid stratification — the natural tendency of warm air to rise and cool air to pool near the floor, which wastes cooling capacity and leaves the upper zone warm even when the floor is at setpoint. Izhar Foster's HVAC design for the METRO trading floor used long-throw diffusers at high level to induct the warm ceiling air into the supply stream, preventing stratification and reducing the effective cooling load on the chiller by recovering heat that would otherwise be trapped at ceiling height.

Specification summary

System	Specification
Central chiller	595 TR LiBr-water absorption, gas-fired, power-resilient
Chiller application	Trading-floor HVAC via chilled water (+7/+12°C)
DX rack	Display cases and back-of-house walk-ins
Open-deck dairy cases	+2/+4°C product face temperature
Frozen reach-ins	−18°C cabinet, −25°C coil
Walk-in cold rooms	+2°C meat / +4°C produce / dairy staging
Panel specification	FireSafe PIR B1, λ = 0.022 W/m·K
Doors	High-cycle insulated, multi-gasket, heated frame, anti-panic
HVAC ductwork	Full trading-floor supply and return distribution
Lahore ambient design	45°C (ASHRAE 0.4%), load-shedding resilience via absorption chiller

Why METRO and why Lahore

METRO Cash & Carry is one of the most demanding retail clients for any refrigeration or HVAC contractor in Pakistan. The global METRO AG specification for its stores is detailed, prescriptive, and audited. Temperature performance, energy efficiency, equipment brand standards, documentation, and commissioning records are all reviewed by METRO's global engineering team against the spec. There is no room for improvisation or value-engineering that reduces performance.

The Lahore HoReCa market is one of the largest in Pakistan — the hospitality, restaurant, and catering sector that METRO serves in Lahore is a multi-billion rupee business that depends on reliable, cold, fresh, and frozen product availability. A METRO store that cannot hold temperature in summer, or that closes during load-shedding, fails its members and damages the brand. The engineering decisions at the METRO Ravi Road project — the absorption chiller, the dual independent refrigeration systems, the high-cycle door specification, the full ductwork scope — are all downstream of that requirement: keep the store cold, keep it open, and keep it compliant with METRO's global standard regardless of what the Lahore grid is doing.

Izhar Foster delivered that. If you are scoping a retail cold store, supermarket walk-in chiller, or large commercial refrigeration project in Pakistan, request a quote with your floor area, display case count, and city. You can also size the back-of-house walk-in load interactively using our cold room heat load calculator. Engineers respond within 24 hours.