HMP RISLEY

Project Highlights
38,308 kWh Saved per annum
20.1 tonnes carbon saved per annum
Reduced energy consumption – 56%
Annual saving in pounds – £3,524
Payback of initial investment – 1.45 yrs

As part of HMP’s Waste Management Strategy Cheetah is now part of the New Kitchen Design Specification. Her Majesty’s Prison Service serves the public by keeping in custody those committed by the courts. Their duty is to look after them with humanity and help them lead law-abiding and useful lives in custody and after release.

HM Prison, as all public sectors, has a statement of purpose, as well as a sustainable development and environmental policy.
They are committed to reducing its impact on the environment by continuously improving the environmental performance of its operations and its estate. Some of their major achievements include a programme of audits and setting up of waste management units at prisons. Waste management units bring many benefits including reduced waste and costs savings.
The aim of their Waste Management Strategy is to

  • Comply with relevant legislative requirements
  • Minimise and recover waste
  • Use recycled and recyclable products
  • Ensure continuous improvement by setting realistic targets and goals
  • Educate, train and motivate staff and prisoners to work in an environmentally responsible manner

The Cheetah system reduces the energy used by industrial kitchen hood supply and extract fans. Based on The Laws of Affinity, fans consume power in proportion to their speed cubed. So the less the fan is used, the less energy wasted. Cheetah controls the speed of the fan by using optic and temperature sensors. The sensors detects heat, smoke and steam coming from the cooking activity and changes the fan speed as conditions demand.
HMP Risley installed Cheetah into their kitchens as part of their waste management strategy. Before Cheetah was installed the combined energy consumption for all of the motors was 69,288kWh/year. After the installation this was reduced to 30,980kWh/year giving a saving of 38,308kWh/year, a 56% reduction.
Due to the success of the trial at HMP Risley the Cheetah system has been included in the New Kitchen Design Specification.
HMP Risley was already taking steps to reduce their energy consumption by turning off the fans for 10 hours over night while they weren’t in use. Previously the fans were running flat out from 5am-7pm. Even at peak times the fan never reaches the maximum speed prior to the installation of Cheetah. In fact it is now using only 44% of the original energy consumed.
Download the full case study here.