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Energy modelling of an existing building based on open data and BIM for efficient facility retrofitting.
UK, London, building 1850th.
(1st stage – initial model), April 2024
A. Problem statement
1. Issues:
- High utility bills, deteriorating indoor quality, reduced commercial profitability.
- Uncertainty about the need for and effectiveness of different building modernization measures and difficulty in selecting the optimal renovation plan.
2. Tasks:
1. Identifying architectural, engineering and operational vulnerabilities.
2. Identification of energy performance potential;
3. Determining usability performance potential;
4. Financial needs assessment.
B. Building Model design.
1. Initial data collection, calculation and processing.
The data preparation stage is the most important for creating an Energy Twin of the research object. Than more detailed the data, than more comprehensive result we will get.
We calculate most of the parameters based on geo-data. For example, insolation data, temperature and humidity data sets for a given part of London, as well as basic geometry and architectural characteristics.
Some of the data is accessible, such as information on construction practices and refurbishment history. For example, this object utilises mechanical ventilation, heating and water heating in the building is provided by a gas boiler
(xxx kW capacity).
Some parameters are entered via an online form.
The online form of digital building carries the function of controlling the parameters for all stakeholders.
2. Initial Building Model design.
Based on the available data, a basic BIM model of the object is developed, reflecting the architectural and structural features of the object. This is a semi-automatic mode of operation in Revit.Autodesk, requiring the participation of a BIM designer.
The final set of prepared parameters, in addition to the BIM model, includes a description of engineering systems and equipment, a harmonogram of usage, properties control systems, human behavior, and environmental conditions. Thus, a primary Energy Model of the real object has been created
Property type
Total floor area, sqm
Main heating fuel
Office
1748
Natural gas
C. Building performance assessment with BIMproEnergy modelling simulator.
The model’s calculation core is based on ISO 52016 – Energy efficiency of buildings - energy requirements for heating and cooling, indoor temperatures and sensitive and latent heat loads, an international standard.
The mathematical model automatically simulates the annual cycle of energy consumption.
In the first stage of the assessment, we use several standard forms that include calculations of monthly electricity and natural gas consumption, divided into ventilation and air conditioning, lighting, office equipment, heating and hot water. For example:
1. Annual energy consumption assessment by end use (Base Run As is):
2. Diagnostics of facility energy consumption.
As part of the task of determining the main directions for increasing energy efficiency for this facility,
The most significant directions for reducing energy consumption while maintaining (not deteriorating) the consumer characteristics of the premises have been identified.
Three main directions for increasing the energy efficiency of the facility have been identified:
1. Reconstruction of lighting (replacement of fluorescent lamps with LED lamps).
2. Modernization of ventilation and cooling (upgrade of standard electric motors to variable power motors).
3. Thermal insulation of external walls (currently there is no façade insulation).
3. Drawing up a recommendation report.
The energy model simulated the facility's annual cycle for each option and assessed their combined impact on facility performance.
This report shows the improvement in building performance as a percentage of the monthly and annual cycle compared to the baseline (as is) scenario, the impact of each retrofit option on building performance, and their cumulative effect.
Summary of the potential contribution of retrofit options to improving the energy performance of the facility. The amount of total reduction of energy resources consumption by items 1-3 in the annual cycle.
The potential reduction in the facility's energy consumption has been identified
D. Summary.
1. In the process of this work, the main directions of modernization were identified and ranked in relation to their contribution to the energy efficiency of the facility.
2. For subsequent more detailed analysis and formation of a roadmap for the modernization of the facility, it is necessary to clarify the description of architectural features, technical specifications of engineering equipment, employee work schedules, the use of electrical appliances for household and professional purposes, details of architectural plans and materials used in the building.
3. It is necessary to determine the objectives of the planned modernization, as well as the format of documents - reports and specifications to be provided to financial institutions in support of the business case and as part of the business plan, as well as to be provided to potential contractors as part of the terms of reference.
4. The created primary BIM model can be used for further development of BIM documentation, and the initial Energy Model can be used as a set of Core Rules for Building Management Systems (BMS) during operation.