Innovative Sustainable Cooling Solutions

Cooling is at the heart of healthy, productive and low‑carbon buildings but it is also one of the fastest‑growing sources of energy demand worldwide. The 2025 CIBSE IBPSA‑England Technical Symposium showcased breakthrough research that is shaping the next generation of resilient, resource‑efficient cooling systems. Below we distil the highlights from four peer‑reviewed papers and reflect on what they mean for designers, operators and owners who are pursuing net‑zero performance today.

1 – Fast‑Track Performance Testing for Early‑Stage Cooling Innovators (Thounaojam et al.)

This study documents the creation and pilot of a practical field‑testing framework that student and start‑up innovators can run in occupied dwellings to prove the cooling impact of their prototypes within days rather than months. By combining low‑cost sensors, a simplified thermal balance and cloud‑based dashboards, the authors show that credible performance evidence can be gathered for less than £150 per test room, lowering the barrier to market entry for disruptive passive and active cooling products.

Why it matters

Start‑ups and student teams often lack the resources needed for laboratory‑grade testing, yet they need robust feedback to iterate rapidly.

Key takeaways
  • A streamlined, low‑cost protocol, developed for the Solar Decathlon India Product Division, allows innovators to demonstrate cooling‑energy or thermal‑load reduction in real residential rooms instead of expensive labs.
  • 90% of teams adopted the method; those who did achieved measurable energy or temperature savings and improved their prototypes between intermediate and final reviews.
  • Survey feedback pinpoints the next frontier: clearer instrumentation guidance, better data‑visualisation templates and extension to humidity‑control technologies.
Implications for practice

Consultants can deploy similar ‘lean’ protocols on live projects, capturing early evidence for passive measures or novel heat‑rejection concepts without waiting for full‑scale mock‑ups. LoraWAN compatible sensors, can be used with VEXO’s S-BMS panels for rapid deployment and data collection.

Interior room with overlayed text highlighting streamlined, low-cost protocol, improved prototypes, and no waiting for full-scale mock-ups

2 –  Cold Thermal Energy Storage for High‑Rise Offices  (Hemarathne & Wijewardane)

Recognising the strain that midday cooling peaks place on urban power grids, the authors evaluate whether integrating cold thermal energy storage (TES) into high‑rise office buildings can cost‑effectively shift demand to off‑peak hours. Using detailed hourly simulations calibrated to Colombo’s climate and tariff regime, the study benchmarks full and partial ice‑storage strategies against a conventional variable‑speed chiller plant.

Why it matters

Day‑time cooling peaks drive oversized chillers, costly grid upgrades and hefty demand charges, especially in tropical megacities.

What the researchers did
  • Modelled three ice/ice‑slurry storage strategies versus a conventional chiller plant for a 26‑storey office in Colombo, Sri Lanka.
  • Simulated on‑peak vs off‑peak tariffs and plant loads to size chillers and storage, then evaluated CapEx, OpEx and payback.
Headline results
Table comparing peak-load reduction, first-cost impact, and simple payback across full and partial thermal energy storage configurations

*Varies with local tariff structure (Singapore < India < Sri Lanka).

Design insight

The partial load‑levelling scheme (Configuration 2‑2) emerged as the sweet spot, delivering > 50 % peak shaving and attractive payback while keeping tank volume manageable.

3 – Balancing Water & Energy in Data‑Centre Cooling  (Elsarrag & Weller)

Water stewardship is emerging as the second critical metric for data‑centre sustainability. This paper expands the typical power‑usage‑effectiveness lens by quantifying how different heat‑rejection configurations trade energy against water withdrawal across diverse climate archetypes, offering operators a quantitative basis for technology selection in the face of tightening regulatory scrutiny.

Why it matters

Global AI‑driven workloads could raise data‑centre electricity use to 6 % of U.S. supply by 2026 – yet many campuses sit in water‑stressed regions.

Study scope
  • Benchmarked four systems for a 125 MW IT load across hot‑humid, hot‑dry, mixed‑humid and mixed‑dry climates:
      1. Air‑cooled chillers (ACC only)
      2. ACC + dry coolers
      3. ACC + wet cooling towers
      4. Wet cooling towers only
  • Normalised results per kWᵢₜ · ΔT to give apples‑to‑apples comparisons.
Findings
  • Water‑only towers achieved the lowest energy use but highest water draw, unsuitable for drought‑prone sites.
  • Hybrid ACC + dry coolers offered the best combined water‑energy cost in mixed‑dry climates, while ACC‑only excelled where water tariffs are severe.
  • A decision matrix helps operators choose technology stacks based on PUE‑plus‑WUE rather than PUE alone.
Take‑home message

Cooling design for hyperscale facilities must optimise both kilowatt‑hours and litres as well as keeping an eye on future carbon‑intensity curves of local grids.

Comparison of cooling systems including water-only towers, hybrid ACC and dry coolers, and air-cooled condensers, with key benefits listed

4  – High‑ΔT Chilled‑Water Systems in Hot & Humid Climates  (Joseph, Wijewardane & Lekamwasam)

With global warming pushing chilled‑water return temperatures higher, this study investigates how raising the design temperature differential (ΔT) across cooling coils from a legacy 5 °C to ASHRAE’s recommended 8.3 °C affects both operational energy and first costs in hot‑humid high‑rise scenarios. A holistic plant‑plus‑coil model captures the intertwined impacts on chiller lift, pump flow, fan power and pipe sizing.

Why it matters

ASHRAE 90.1‑2016 mandates ≥ 8.3 °C ∆T on coil selection, but many South‑Asian buildings still default to 5 °C.

What was tested
  • Three coil/plant configurations (ΔT = 5 °C, 7 °C, 8.3 °C) for the same Colombo high‑rise.
  • Used detailed load/sizing software plus AHU‑coil selection to capture both water‑side and air‑side impacts.
Results at a glance
  • Pump flow fell 40 % and pump energy dropped almost 40 % when moving from 5 °C to 8.3 °C ΔT.
  • Overall chiller‑plant energy fell ≈ 5 % despite a slight rise in fan energy and coil size.
  • Capital savings of 2.8–3.6 % thanks to smaller pipework and pumps.
Design note

Pair high‑ΔT coils with variable‑primary pumping for maximum benefit, and validate control stability during partial‑load operation.

5  – How VEXO’s Side‑Stream Filtration Supercharges Sustainable Cooling

Every one of the studies above relies on stable heat‑transfer surfaces and clean hydraulic circuits. That’s where VEXO comes in.

The X‑POT™ difference

VEXO’s patented X‑POT side‑stream filtration units combine magnetic separation, bag/cartridge filtration, air & dirt separation and chemical dosing in a single, compact vessel. By continuously diverting part of the total system water volume, X‑POT units:

  • Remove suspended solids and bio‑film that choke coils and foul plate heat‑exchangers.
  • Slow corrosion & scale at source, safeguarding chillers, TES tanks and pipework.
  • Maintain water quality in line with BSRIA BG 29/50, protecting warranties and enabling predictive maintenance.

Case studies have shown up around 19 % savings on pump energy alone and immediate resolution of blockage‑driven failures in critical environments – including MRI suites and hyperscale data halls.

Proven in Data Centres
  • Continuous, low‑pressure drop filtration keeps CRAH coils, micro‑channel condensers and CDU loops free from debris.
  • Compatible with liquid‑to‑chip and rear‑door heat‑exchanger technologies where particulate purity is paramount.
  • Modular designs scale with the size of the system.
Ready to elevate your cooling project?

Our engineering team has deep experience supporting consultants through:

  1. Design integration – hydraulic schematics, duty sizing and controls sequencing.
  2. Specification writing – model selection, water‑quality KPIs and BMS points lists.
  3. Commissioning & training – ensuring performance is locked in from Day 1.
Diagram of a water treatment system showing dirt and air separation, additive dosing, magnetic removal, and dirt filtration components

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