Central Plant Optimisation software – better energy savings than BMS control alone

More than 35 percent of the power required to run a building is consumed in one place: the central chilled water plant. While there is value in connecting the building management system (BMS) to schedule plant run time, very little beats central plant optimisation (CPO) software for true energy savings—it optimises the performance of all components.

While CPO solutions have been available for some time, organisations are often assume that a BMS performs the same function so having both is an unnecessary duplication. While BMS’ can apply general rules, such as scheduling outputs according to occupancy levels, it’s CPO software with its ability to constantly and consistently maximise the efficiency and performance of the entire plant, taking into consideration all plant components, as well as unique variables, that is delivering true breakthrough benefits.

Why is CPO important in South Africa?

South African organisations must lower energy consumption to address the country’s twin challenges of insufficient energy capacity and rising costs. Budgets are under pressure but, at the same time, organisations are being compelled to reduce their carbon footprints.

Many are taking the common-sense approach of replacing old plant equipment and systems with high-efficiency systems, such as variable speed drives and BMS technology. While both offer benefits, they are discovering that it is CPO technology takes optimisation to the next level.

The hands-free relational control technology embedded in CPO solutions is able to constantly, consistently maximise the efficiency and performance of the entire plant. It takes into consideration every component part, including the chillers,  pumps and cooling towers, and in addition it factors in primary as well as secondary and tertiary circuit components in large installations, aligning them with demand and site priorities, and optimising performance and outputs.

Setting CPO up

CPO is a stand-alone unit that communicates with plant components and the BMS using standard protocols (BAcnet). It requires some setup. To optimise performance of the plant, it’s important to ensure unique variables are integrated into decision-making and site priorities are set.

CPO software takes multiple variables into consideration, pinging plant components for information but also tapping in the BMS and big data where relevant. Variables may include the combination of equipment on the site and its configuration, equipment conditions and availability, occupancy levels, ambient environment, operating conditions, the weather forecast and more. CPO also takes note of configured site priorities – some sites, such as pharmaceutical manufacture or ICT hosting facilities, may require always-on environmental control; others will happily shut plant equipment down when the building empties.

Because there is now so much information available and the cost of getting it wrong is so high, manual central plant management, which is exposed to human error, has become almost irresponsible. Consider the annual cost of running a plant at even 30% higher capacity than is necessary for a year, or the cost of shutting chillers down even just two hours later than is needed every day.

Benefits of CPO

• Cost effective optimisation based on proven best practices for any system type/configuration (24 standard chiller plant profiles or custom configuration)
• System is configured on-site with no disruption to operations
• CPO is compatible with most building automation systems
• Real-time dashboards to view operating efficiency, and view trends.

The more you know about your plant performance, the more energy you can save. CPO gives organisations immediate access to critical information, giving them the visibility they need to manage energy and operating costs and significantly improve the performance potential of their plant for years to come.

CPO’s web-based, real-time measurement, verification and management dashboards make equipment performance more visible. It will continuously collect, analyse and report on plant operating data, enabling the organisation to view operating efficiency in real time, as well as see both short and long-term trends.

CPO will become critical

CPO is going to become critical to maximise the operational efficiency of chiller plants and lower energy usage and cost. Just take a look at the CPO solution we have deployed at Stanford University. Similar implementations are already happening locally, with great results.

By Russell Hattingh Engineering Manager, Johnson Controls Systems & Service, South Africa