HEATWAVES | COOLING STAYING COOL AT 40C After thermometers hit 40C for the first time in the UK, we asked consultants and manufacturers how future buildings can be kept at a comfortable temperature without increasing energy costs Tim Mitchell, sales director at Klima-Therm A dopt a fabric rst approach to building design, maximising the performance of the components and materials that make up the building itself, before considering the use of mechanical or electrical building services. Part of this involves designing buildings to be low energy in the rst place: well-insulated and sealed to reduce winter energy demands, but avoiding the danger of overinsulating that creates summer overheating problems. If possible, use exposed slabs to absorb heat and create height in the space. This allows warm air to rise and be removed from the space. Exposed slabs also allow for overnight purging of the building to store coolth in the slab. Use smart building principles to share energy between local users. For example, cooling means heat rejection what can you do with that heat? You might, for instance, place data centres and ofces near leisure centres, hospitals, and residential hot-water and heating demands. Next, choose high-efciency central plant there is no better way to get a return on investment, not only for owners and tenants paying the bills, but also for landlords. Their asset is worth more, as it can be let for more to tenants, who tend to stay longer and if renters do move on, an efcient building can be let more quickly. Efciency comes in many guises. Best-in-class equipment is one way to go, but another is to use energy storage and recovery, which can allow one energy input to do two jobs. A good example of this is the hybrid four-pipe Rhoss EXP/HT heat pump, which can produce independent cooling and heating, but when cooling the heating can be free essentially, because of heat recovery, and vice versa. Susan Hone-Brookes, director of sustainability at ChapmanBDSP W e are all familiar with the worrying stats on increasingly extreme high summer temperatures. The cost-of-living crisis and focus on reducing carbon emissions during the winter months pushes building design down the route of a wellinsulated, thermal box, which then struggles to perform well in high temperatures. Our tortuous fenestration dance between wellbeing daylight levels and limiting solar gain is one that we perform daily. Many clients are constructing residential apartments in urban settings where cooling is not the norm. Mechanical cooling, generally direct expansion, xes the immediate issue, but with the payback being increased energy consumption costs and carbon emissions. It can also exacerbate the urban heat island effect, which can increase external summer temperatures by up to 7C in London. The ability to carefully select fabric elements and fenestration design has, over time, hit the buffers, with a maxing-out of what can be considered commercially viable today. Furthermore, we still operate within an industry that shies away from technology input, so suggestions of phase change materials and PV-plated windows are still considered whimsical, and dismissed quite early in the design process. We believe we are now at the very edge of what we can do passively with residential tower blocks in urban settings without a wholesale change to the design, look and feel of the architecture. That means a holistic rethink on inception design solutions, and adaptation strategies for existing buildings. This needs to encompass new technologies, mass/form, and so on, but also how occupants inhabit the building. www.cibsejournal.com September 2022 75 CIBSE Sept 22 pp75-76 Cooling in hot climate.indd 75 26/08/2022 14:04