Building automation: Capturing the capabilities
An explanation of the capabilities of building automation systems and what’s required to get the best out of them is provided by HARALD GRABNER of Efficiency Matters.
The purpose of a building automation system (BAS) is to increase the efficiency of daily operations, reduce energy and water consumption, provide advanced indoor comfort and deliver real-time building performance data. How does a BAS achieve this?
Let’s have a look at an average office building – 20 storeys, food outlets in the basement and three floors of underground car park. Each tenancy has individual air-conditioning and lighting controls. Base building services for each tenancy are metered. Two floors are dedicated to meeting and conference rooms, which can be booked via a central booking portal by each tenant. Each meeting room has separate air-conditioning and lighting, which are both metered. The same applies to the food outlets. All base building services, such as lifts, lighting and water, are also metered. Air-conditioning and associated heating and cooling plants are controlled by the building management system (BMS) while all meters are read and monitored by an energy management system (EMS). Other building systems – for example, access control and fire services – are individually controlled. Each of these systems are integrated into the central BAS. Furthermore, the BAS is capable of exchanging financial data with the building management company’s accounting system.
BASs do apply to special purpose buildings, such as industrial facilities, shopping centres, hospitals and aged-care facilities, as well; however, they are not in the scope of this article.
IMPROVED TECHNICAL PERFORMANCE
Modelled occupancy patterns based on access control data allows air-conditioning to operate ‘just in time’ when people are coming in rather than running ‘as per lease’ on fixed hours. The access control data can also be used to shut down individual lifts in times of less people movement, for example after hours and on weekends.
When a meeting room is booked, lighting and air-conditioning is switched on early enough to have the room at a set temperature when the meeting starts. Advanced systems also allow for audiovisual equipment, catering or other special requests to be charged to the tenant.
Meter readings from the EMS can be used to generate plant and equipment profiles to compare (for example, with BMS logs), analyse and optimise operational strategies. This is particularly helpful when investigating peak consumption and how to shift potential plant operations to non-peak periods (this usually requires some kind of engineering to reorganise plant and equipment).
Furthermore, meter data and booking records can be used to calculate the building’s energy performance against set benchmarks such as a NABERS rating. If major equipment has been upgraded or replaced, this also allows the comparison of proposed performance against what is actually achieved. Plus it allows the charging of tenants for their use of meeting rooms instead of a fixed ratio, for example per metre squared.
MANAGING DAILY FM TASKS
The above examples illustrate how a BAS can improve a building’s ‘technical’ performance. Another, maybe even more important, feature of a BAS is how it handles the daily tasks of the facilities management team; for example, tenant requests, preventative and reactive maintenance. This is far more than a ‘maintenance log’. Core to this functionality is a database of (almost) all major items of the building, regardless of whether it is owned by the base building or a tenant; for example, chiller pumps, lift motors, supplementary air-conditioning, room and facility IDs for unique identification, printers and appliances.
If this data is used by a BAS, pre-set action plans will allow users of the BAS (not necessarily limited to the facilities management team) to action issues quickly and easily, often without needing to place a service call. This saves time and money, and keeps back-of-house operations running much more smoothly. A BAS does not avoid issues within plants and equipment; however, it will reduce downtime significantly.
LIFE MADE EASIER
Here’s an example of how a BAS can make life easier: the dishwasher in a tenant’s kitchen (provided by the building) doesn’t work. The manual has disappeared and the error code is more confusing than helpful. After logging the issue – with the error code – the tenant receives an easy to understand, step-by-step to-do list to resolve the issue himself. If this isn’t successful or some sort of ‘handy job’ needs to be done (for example, connecting the water hose to the machine), the facilities management team takes over and tries to fix it. If this also doesn’t solve the issue, a service call is placed. But, the service contractor is not only called on-site, they also receive all the information on how the tenant and the facilities management team have tried to solve the issue. This will give the contractor a good understanding of the situation, will save time on-site and even preclude a second visit, as parts can already be organised.
In terms of maintenance and plant issues, the same action plan methodology is applied. For example, if room temperature goes above its set point, the person in charge (let’s call them Alex) logs the issue and gets provided with an action plan on how to address the issue. It turns out that the issue is a faulty valve motor. Alex locates the valve in the plant room, checks the motor – he has a PDA that allows him to access the BAS everywhere within the building – and needs to place a service call to the contractor. The contractor receives all the information in regards to the motor and valve, so he can get the right parts or a new motor. If he has to order it, he will comment on the BAS, so Alex and the requester know that the issue needs a certain amount of time to be resolved.
The feedback from the contractor is very important in terms of tenant satisfaction and avoiding complaints, as often the information – in this case, parts need to be ordered and the temperature may be high again the next day – is not forwarded to the requester, due to the fact that it has to be done manually (for example, emailing or Alex has to comment on the maintenance log on his computer). To do this, Alex needs the time to access the log, which often isn’t the case as other issues require his attention. If information is put into a BAS, it is automatically delivered without taking up people’s time.
Both examples illustrate the main function of a BAS: collecting and providing information from and to different operating systems – such as a BMS, EMS and room booking systems – by communicating them in a pre-defined way to all users of the building, so that all actions are recorded and anyone who gets involved has access to the actions taken, so they don’t repeat actions that have already been completed. This is how a BAS achieves savings of financial and natural resources and improves the daily performance of a building.
GETTING THE BEST
What is required to implement a BAS and to harvest the benefits? First and most important is understanding what the capabilities and limitations of the building are and what the BAS is supposed to achieve. What are the conditions of the building now and how do you want the building to operate? If the goal is specified, the question then is how to get there?
To specify the goal, it is important to grasp how much of a building’s operations need to be covered by a BAS. Who is going to use it and are these parties willing to pay their share? If no shared meeting rooms exist, this functionality is not required. In this case, all-in-one solutions may be a waste of money. A modular system may be a better alternative, as they can be added anytime if required.
Also, keep in mind that any BAS needs to be tailored for each building. This means that even modular systems require additional time and costs, which can vary significantly from supplier to supplier. Furthermore, ongoing support is crucial as a BAS needs to be flexible and adjustable to any changes – even minor changes – within a building.
Harald Grabner is the owner of and a senior sustainability engineer at Efficiency Matters.