Buildings account for 40% of global emissions and in the UK 30% of emissions come from the building industry, mainly through operational in-use from: heating, cooling and electricity usage. How can we create smart buildings that could respond in real time to changes in occupancy and air quality to save on energy and create healthy efficient workspaces?
This solution was sourced in response to one of UKGBC’s past challenges on ‘Linking Building Occupancy to Energy Use’.
LightFi is an Internet of Things solution that uses WiFi radio to measure occupancy count and retrofit buildings. LightFi design occupancy sensors with optimising energy efficiency in mind, as well being able to monitor CO2 levels, air quality, temperature and humidity. The data from sensors is available on an online portal for monitoring and analysis. LightFi provide direct integration to a building’s building management system, with no rewiring required and retrofit mini-HVAC-version equipment with relevant strategies to automate commercial and public buildings. Responsive HVAC capability based on real-time demand reduces energy use when space is under-occupied. LightFi automatically reduces the HVAC loads when demand starts to fall, to make sure air is not cycled unnecessarily. The more dynamic the occupancy patterns, the more energy LightFi saves by allowing the building to “breathe” in sync with live usage patterns.
By adjusting energy use to real time occupancy data, LightFi quotes:
- Up to 25% on energy savings each year.
- Savings of up to 150 tonnes of greenhouse gas emissions per year for a 10,000 m2 building – equivalent to 10,000 trees planted every year.
Costs include sensors, ‘Software as Service’ subscription, travel for installation and, if required, building management system integration and control. The costs vary depending on the size of the project but the approximate return on investment is 1.5 years.
For a pilot installation over a 1000 sqm open-plan office space, eg one floor, estimated total costs might be: £1,500for sensors, £500 for data subscription and £400 on travel for installation. Costs and timings will vary depending on the infrastructure, location and age of the building. For BMS integration and control LightFi recommend rolling out for a whole building. The costs and ROI vary depending on building age and infrastructure. An example retrofitting a 10,000 sqm building are: Sensors (minimum) and BMS integration capabilities: £19,000, BMS commissioning and cabling: £12,000, SaaS subscription and monitoring £4,000, Energy saving pre-COVID-19 £30,000, post COVID-19 potentially more due to lighter utilisation. This could result in a Return on Investment of approximately 1.5 years.
LightFi worked on a 10,000 sqm office building in Leicester in 2019 to detect occupancy levels accurately, securely and anonymously, in all variety of spaces, to enable real-time demand-based HVAC control. Only 18 sensors were needed and cabled-in throughout the building. This made the installation quick, cost-effective, and non-disruptive. The LightFi system is saving 2,500 kWh per week on the mechanical load, equivalent to approximately £18,000 annually. Phase 2 of the project (where LightFi will work to allow more granular control of AHU speed for the building) is projected to provide estimated energy savings of £60,000 per year – approximately 22% of the building’s annual HVAC energy bill.