A failproof checklist of #10 steps to an optimised HVAC installation.
If anything, providing the right level of comfort for your building, is the least your installation should do. Sadly, many even fail at that. As a building owner, your heating and cooling installation is expected to just work. And preferably as efficiently as possible. However, many are suffering from a much higher energy consumption and carbon emission than anticipated.
A good start is half the battle
When asked if building owners were happy with their installation ‘as is’, few responded positively. High energy costs, comfort issues in the building, heat pumps or CHP’s that aren’t working as well as anticipated, installation costs ending up higher than initially budgeted, etc. are just but a few of the common complaints that were given. What the exact root cause is for these issues, is often much harder to pinpoint.
There are many different stages in a project. From design, through installation and commissioning, and finally the further live cycle management of the system. A good and solid conceptual design is the perfect head start for a successful project, and the importance of making the right choices from the get-go is crucial. During this stage, the main technologies are selected, as well as the hydraulic configurations in the plantroom are laid out. They define the expected heating and/or cooling load per circuit. During this design stage, different system alternatives should be analysed and compared based on project KPI’s. Throughout dynamic simulations that show different system alternatives, your M&E consultant can objectively show the expected performance of the design. In reality, building owners usually only get one concept during this stage, often based on previous projects and there is no way to tell whether this concept meets your KPI’s.
From design to reality
The last and final stage? Translating the design concept of the M&E consultant to an executable design. This requires extreme precision. The smallest miscalculation can throw off the whole balance of your installation. Unfortunately, system components (pumps, control valves, balancing valves, etc.) are calculated using predominantly “rules of thumb”, rather than accurately been calculated through an iterative process. This often leads to seriously oversized systems. Once installed, the installation must be commissioned to work ‘as per design’. The balancing valves have to be set to the right preset to meet the required design flow rates in the system. So, you can see how first time right is of great importance?! If not, tweaking some presets trough a trial-and-error process, until the overall system behaviour looks acceptable for that specific load, will only throw off the hydraulic balance, leading to comfort complaints.
The checklist of all checklists!
Want to regain control as a building owner? Follow this simple checklist, to put you back in the driver’s seat. It all starts with specifying the use of a design and dynamic simulation software in the tender/RFP. This will prove the performance of the design. With such a professional and specialized software, the supplier should be able to provide the following:
- Model and simulate different system alternatives
- Sensitivity analysis on the sizing of the different production assets/TES/temperature regimes and other important design parameters
- Graphs of the operating flow and return temperatures, flow rates, efficiencies, SCOP’s, load duration curves, etc. particularly showing partial load behaviour
- Analysis on CAPEX, OPEX, Carbon and Comfort of each concept
- Science-based performance results for efficiencies, heat load contributions and run hours of main production units, distribution losses and pump consumption.
- Clear reporting on the different alternatives for your system
- Optimised component calculations which proof the iterative relationship between every component (pressure drops).
- Component schedule including all specifications (pump heads, Kv value + flow rate of the balancing valves with the presets, Kv’s values of the control valves and the valve authorities, pipe selections, etc.)
- Full control logic of this design, detailing all controllers, time delays, setpoints, time schedules, … for an optimal BMS integration
- Demand a HVAC Digital Twin which accurately represents your installation such that this asset can be used for further life cycle management of your installation
Requesting this list of design outputs, will provide objective proof of the performance of your installation, and thus put you back in control of your project. Your supply chain should be able to provide full transparency on the performance of the design choices, at any given moment. Before the handover, the Digital Twin can be used for commissioning review to assure correct installation and commissioning. On top of that it also helps within performance management, any changes or expansions of the installation and further integration of low carbon heat sources during the operational stage.