Client: John Gilbert Architects / Glasgow Life
Services: Technical Survey & Options Appraisal
Renewables: Ground Source Heat Pump & Air Source Heat Pump
Technical Assessment & Review
Langside Library is located in the south side of Glasgow. The main building is thought to date to pre-1919 whilst the extension is thought to date the 1960s. The client wanted to review the existing services and look at options for net zero for the site. The central heating was a gas boiler from the 1980s.
The preference of the client is to obtain a “net zero” carbon building but also reliable and high comfort factor in terms of services.
We used IES three-dimensional dynamic modelling software to establish the site heat demands.
We also measured the air tightness onsite to ascertain the ventilation heat load more accurately.
Dynamic Thermal Analysis
The property had a detailed thermal model produced in IES-VE. This allowed us to run several simulations to show an accurate replication of the building performance down to a 10-minute resolution. This kind of detailed resolution is important in buildings with a good deal of variation in occupancy levels.
This allows balancing the high occupancy loads and maintaining a comfortable environment with out oversizing the equipment.
It takes some time to get the quality and level of detail in the model correct, but it is fundamental to the value of the output for all the work that follows.
Heat Load Modelling
Conventional ‘steady-state’ heat load calculations often result in oversized heating plant requirements.
This is because the building can hold onto warmth from the previous day instead of beginning each day completely cold. It can also capture heat from the sun during the day and slowly release it into the rooms at night.
We employed the IES model to assess the site’s heat requirements, which took into account factors such as annual occupancy patterns, activity types, and heat and hot water demands. Using this information, we predicted heat demands, considered gains from sources like solar and incidental heat, and accounted for losses in fabric and ventilation.
In accordance with the energy hierarchy, work was commissioned by the client to look at the building fabric levels as a priority.
Using the thermal model, we could quantify each of these proposed measures and rank each one against an energy consumption prediction and nominal budget cost. This allowed the client to prioritise the most cost-effective options.
The options for heating tend to be:
- Air source heat pump
- Ground Source Heat Pump
- Electrical Radiators & Immersion (for DHW)
- Biomass- Pellet boiler
- Gas, LPG, or Oil boiler.