What are the most effective strategies for reducing energy waste during low occupancy periods?

Few things that I have found useful are: 1.Good building design- If due consideration is given to passive design aspects of a building also e.g building orientation, insulation etc at the time of design, these can help reduce energy wastage across the building lifecycle. 2.Instrumentation, controls system and good data can be very important to identify energy waste and potential opportunities. 3.People counting- only when you know count of users in a given zone, at a given time, with reasonable accuracy , you can adjust/ modulate a system be it HVAC or lighting or any other to reduce energy wastage. 4.user connect- users can be the best sensors in a building, it is imp to make them aware and equipped to help reduce energy wastage.

Consider using Feed Forward control processes to avoid overshoot and undershoot. This can be used in conjunction with PI and Trim & Respond processes. Feed Forward processes use a combination of historical performance with data analytics to predict near future requirements, so that you can slow down or speed up equipment output just prior to required changes. This is much better than making output changes after sensing devices request a change due to overshoot or undershoot. It’s a bit like AI, but it’s been around for several years in the industrial control industry.

Step 1 - consolidate the employee to one location Step 2 - shutdown the AHU and run few hours in a day to ensure the carpet and furniture are not impacted due to high humidity Step 3 - run a smaller chiller capacity due to low heat load Step 4 - increase the leaving chill water temperature higher if you don’t have a smaller chiller capacity

The most impactful change to be made in an HVAC system to account for low occupancy is reducing the unoccupied minimum air flow setpoints. This impact is contingent upon having accurate occupancy schedules. this is achieved through either occupancy sensors for direct measurement or through time-based schedules. There are many factors to consider but the main point is to have the minimum air flow setpoint of all terminal units during unoccupied times set as close to zero as possible. The next most important thing is to make sure the air handlers can and do respond to what the terminal units are doing. Supply air temperature and pressure and outside air quantity should all vary based on what the terminal units are doing.

Schedule it via Building Management System and increase temperature and reduce air changes. You’ll generate savings beyond expectations

1. Leverage on direct free cooling if available. This approach can be very effective in regions with favorable climate. 2. Insulation of building envelope (sealing doors, windows etc.)to reduce heat gain or loss.

Technology is amazing. If feasible, select LED fixtures that have dimming, daylighting, occupancy counting, and individual addressing built in. These fixtures give you a massive amount of data with which to control your other systems. Further, they allow you to granularly tune your lighting levels and hold a max illuminance level to prolong fixture life. Consider how loaded your heating systems are in the winter. If they're maxed out, an LED conversion may necessitate upgrades or adjustments to the central heating.

This is a no-brainer for any energy reduction strategy. Make sure you specify clearly the lux level, fitting design and colour range. It may take some time for colleagues to adapt to the new lighting but you can make the transition softer if you put effort in designing the right lighting profile.

With understanding that we are talking about extended periods of low occupancy I fully support 4 Steps suggested by @Pusparajan. Additionally: - walk unoccupied space and ensure that windows and doors are closed, thermostats are are set for min consumption, lights are off, all non-crucial equipment is unplugged. - If there is no crucial equipment - cut electricity at breaker. Lock the doors leading to unoccupied space if possible. If unoccupied areas can not be locked off - repeat the procedure every week.

From my experience, switch to LED lighting has multiple positive benefits. In the offices, we replaced 165 old fluorescent tubes with efficient LED tubes. Project was less than one month long, including planning and implementation, and payback period less than 2 years. We are in the 3rd year of implementation and project and investment already repaired itself. Every tube is still working perfectly. On top of energy and monetary savings, we achieved optimal light colour and comfort in the office, and eliminated flickering effect of old fluorescent lights (harmful to eyes and causing headaches).

Use submeters to understand your baseload consumption when the building is not in use, and if it is significant, address what equipment are driving it. A good energy monitoring and targeting system can give you some great insight into your building energy consumption.

COLLABORATE WITH THE IT TEAM! Huge savings can be realized by implementing standby load elimination, especially with a computer heavy office. There are a zillion ways for the IT team to reduce computing power during off hours and working with them to find the best solution that works for everyone will yield great results!

Power Management is even in your own house, turn off lights that you dont need, set your TV on power saving mode, unplug adapters or you can masure your load when you are not consuming it. Like when i leave for vacation i set heating, fridge etc on vacation mode! Also consider buliding or Office like your home in Power Management

From a weekly perspective, Monday to Friday approx 10h/day the corp office is used 29.7%. Desig properly the electrical panels and include programmable time switch for most of the open space workplaces. Easy fix to switch off 1233 docking stations D9Y19AV with 65W chargers and 1843 Dell P2417H monitors that will equal approx stand by consumption outside working hours of approx 60,000 kWh/year. IT racks could be stacked according to the business model and security levels to allow a cooling optimization. CRAC units setpoints might be increased slightly from 21°C towards 23°C if possible. Each degree can ensure savings by decreasing the operation time by approx 6% to 12% depending on the heat gain rate of course.

User do not follow instructions and always forget to unplug the device, in which case the device charges to work all night. To fix this problem I started switching off the workstation power supply from DB's it helped me save electricity.

Consider nominating a site Energy Champion if you are a multi site organisation. Be clear on what you would like people to do, and share the progress with everyone. People like to see the result of their actions and be rewarded for it, an energy champion badge, or email signature banner can go a long way!

The most important perspective is the culture part. As it is said “Culture eats strategy for breakfast” Regardless of the best strategy, if culture and mindset are in other direction, you’ll be back to where you started.

Behavior change is one of the most effective ways to improve energy efficiency. Most companies ignore to raise awareness across the entire company and not informing security and cleaners who, in most commercial facilities, are responsible for the night load, raising awareness goes a long way in energy management.

Beware! Ensure the energy consuming systems affected by staff are prepared for the changes encouraged! I've seen energy consumption spike at 5:30pm when everyone leaves the office and, wanting to save energy, turns up the temperature on the thermostats. The system wasn't programmed to respond correctly to this and the only thing those staffers accomplished was drastically increasing the reheat energy being consumed. Train all staff, office and facilities, towards the same goal. Have rigid building hours to enhance effectiveness of air conditioning scheduling. If the type of work being done allows it, group people in an open office by temperature preference.

The few occupants of the office should be encouraged to use twice the same cup of coffee or water glass if there is a kitchenette with washing machine to reduce the use. Coffee machines can be programmed to switch off and on. The most energy intensive would be a milk cooler for the coffee machine, pay attention to that one, track consumptions. Identify your SEU - significant?energy use.

All of the suggestions are very good and I have put them in practice in my previous role. But one thing that is really challenging is to prove financial and environmental benefits for the projects because the cost for viabiliziation sometimes is high. One thing I learned in my current role is that it is possible to buy service from companies that are interested in investing in your facility (related to enegy) and receive the payment based on the reduction they make in your eletricity bill. That is amazing. Not only you dont have the initial expense/investment but also you have the proven benefit in your bill.

Automate and optimise the system wherever possible. Appoint energy manager, who can be also contact point for other employees.

The Energy Performance Certificates (EPCs) were introduced in 2002 by the Energy Performance of Buildings Directive (EPBD, Directive 2001/91/EC1) as a mandatory requirement for the EU Member States. Starting Apr.2027 a registered EPC certificate of minimum C could be presented across EU. Starting Apr.2030 is expected a registered EPC certificate of minimum B across EU to be required The assessment methodology can vary from country to country as per an appropriate selection of the default values that may increase the reproducibility of EPCs and may reduce the total inaccuracy of the assessment procedure to around ±15 % across EU. The EPC will identify recommendations that could be eligible for Green Deal financing.

1) Optimized Floor/Plant Design in the initial phase by concentrating critical personnel in specific areas allowing for targeted HVAC cooling, minimizing the utilization of chillers or employing individual cooling units to reduce energy consumption. 2) Installing LED lights with motion control switching ensures that lighting is only utilized when needed, reducing energy waste in unoccupied areas. 3) Maximizing the shutdown/ Unplugging of appliances and equipment in unused areas helps further conserve energy. 4) Educating occupants and building a culture of energy conservation is a must in the long term.