Make better energy choices with building simulation: Test your energy optimization ideas and indoor climate in a virtual environment

It is certainly not a new thing to use building simulation software to test your building’s performance – but in the pharma industry, focus has often been to optimize only the processes and not the building shape and utilities. When building a digital twin of the facility, it is possible to test the effect (and derived effects) of changes to everything from the ventilation system, solar shading, lighting or constructions.

The bigger picture

In a building, it is the need for a comfortable indoor environment that consumes energy. Up to 90% of the typical building’s (not pharma) lifecycle carbon emissions occur during the operational phase, mainly as a consequence of the heating, cooling, HVAC, lighting and appliances.

There is a lot of uncertainty involved in choosing which energy optimization initiatives to implement. Which idea is the best? How will the different ideas work together? How much can you actually save? Often, energy savings are calculated in individual excel tools, but when working with complex interconnected systems such as a facility, we need to look at the bigger picture.

Here is an example: When you change the lighting system in a building to LED, the electrical consumption is reduced significantly – but the derived effects include a lower heat gain and thus a reduced need for cooling and maybe even an increased need for heating in the facility. Hence, if you want to optimize a building through multiple initiatives, the total energy savings is not the sum of each of the initiatives, since one initiative may compromise another.

The total energy savings is not the sum of each of the initiatives, since one initiative may compromise another."

A digital building model is really handy for testing combinations of different ideas to find the best and most economic setup. Advanced building simulation software allows you to specify each energy consuming system in detail and predict the interconnection of these systems. Results are generated on a similarly detailed level, enabling designers to investigate for the optimal fit across all professional disciplines. When working with energy optimization in pharma facilities, many disciplines are involved; architectural, electrical, HVAC, utilities (clean and black), building utility to name a few. Importantly, each initiative must be studied and verified in relation to good manufacturing practice.

Building simulation software in the pharma industry

The processes involved in producing a medicinal product (sterile or non-sterile) are typically very energy intensive. Hence from an energy point of view, the overall benefit of improving a facility’s building parameters, such as constructions, windows shell and detailed control of the indoor environment in relevant areas, is marginal compared to total energy consumption of the facility.

Fortunately, the use of simulation software in the pharma industry is gaining more ground, since the tools allow for investigating creative solutions across the interface between the facility processes and the building operation. An example is reuse of waste water for heating purposes. Additionally, it is possible to perform analysis into setback of HVAC systems in classified areas or in areas with large air exchange, to investigate for impact on temperature, humidity and other parameters, without the risk of harming the product.

Heat gains

Figure 1: Example of a simulation result showing heat gain in a room in 7 days. The curves are the sun (weather data), appliances and equipment, lighting and occupants

Temperature

Figure 2: Simulation results showing room temperature in three different HVAC control strategies

HVAC

Figure 3: Example of detailed representation of an air handling unit with active and dynamic components

3D model

Figure 4: 3D building model placed in a virtual environment

Bridging the gap between predictive measures and real systems – evolvement of the digital twin

Building simulations tools are commonly used during the design phase. However numerous studies have shown that actual building performance often deviates significantly from the predictions observed in the building simulations. The gap is typically known as the “performance gap”. The gap occurs when the digital building model lacks precision in predicting the uncertainties that buildings are subject to, such as weather cycles, facility usage, occupancy and system degradation.

In order to account for these uncertainties, the digital models must be continuously calibrated with information obtained from the building monitoring system (operational energy loads, metered data) and from sensor recordings (temperature, relative humidity, CO2 and occupancy). This data is then imported into the model as updated profiles and new simulations are performed. By performing this process continuously, the digital twin evolves in parallel with the actual building. In this way, it becomes possible, for instance, to produce highly efficient operational and hence energy-optimized plans for HVAC, lighting and utility systems tailored to both building and user needs.

Building simulation in short

To be able to do building simulations, an extensive digital model is needed. The model must at least include:

  • A 3D model of your facility (or the affected part) including building shape, orientation and windows with thermal properties to all the elements (e.g. U-values, G-values)
  • Configuration of the ventilation system, building utilities and solar shading
  • Indoor climate requirements such as temperature, humidity, air quality, etc.
  • Usage profiles containing occupancy, internal gains, lighting, etc.

The model is placed in a virtual environment with geographical weather data, and simulations on energy consumption and/or indoor climate can begin. Compatible software includes B-SIM, IES-VE and IDA ICE.