When we were invited to craft a new solution for the Millenium Seed Bank at the Royal Botanic Gardens, Kew and Wakehurst, we were more than happy to help protect the world's largest collection of seeds and some of the most threatened plant species using our bespoke CO2 system.
Co2 Seed Preservation Project
Constructed in the year 2000 at the Royal Botanic Gardens Wakehurst, the Millennium seed bank is home to the world’s largest collection of seeds. One of the prime objectives was to conserve the world’s threatened plant species. Currently 15.6% of the world's wild plant species are banked at Wakehurst .The seeds are required to be stored at -20℃ and are kept in a state-of-the-art bunker – flood proof, bomb proof and radiation proof - for protection. When the Seed Bank was originally commissioned a R404A refrigeration system was installed to provide the required cooling for the seeds.
As the service provider for Royal Botanic Gardens at Kew and Wakehurst, we identified the need to provide not only an alternative, but temperature control resilience to ensure the safety of the collection. We discussed the possibility of a natural refrigerant option more in line with the seedbank’s ethos of sustainability. We provided a selection of proposals including Ammonia, R449A and CO2.
Co2 Technology Research and Development
Extensive thermodynamic and life cycle modelling of the various options including the currently fitted R404A systems were undertaken. The results were presented to the client including considerations of the efficiency, capital cost and life cycle costs. The solution: a Low Temperature Transcritical CO2 booster system, reducing direct energy consumption by 20% and saving 26 tonnes of CO2e per year in Total Equivalent Warming Impact (TEWI).
We provided a full design package for the client including load calculations, pipe sizing, isometrics and a full list of parts to ensure the installation worked holistically and seamlessly. The refrigeration plant is capable of providing 77.5kW of duty at an evaporating temperature of -30C.
Bespoke Co2 Solutions
This bespoke solution, based on a well tried and tested industrial product platform, has been designed and built to achieve the highest levels of resilience and efficiency:
Ultra-high resilience 120bar/80bar system design – means no risk of venting refrigerant during a power outage.
N+1 on all key components - throughout the system and single point of failure has been eliminated.
Arctic Aurora optimised controls.
Industry leading high efficiency compressors with positive displacement oil pump
Multiple frequency inverters.
LT Ambient rejecter and wetted pad gas coolers ensure high ambient temperature resilience & performance.