Greetings! I have recently taken charge of a Building Management System that has not been performing up to par since its installation. The system consists of a ControlLogix main unit with wireless communication to a Micro820 unit located on each roof. The Micro820 units are equipped with temperature sensors, which enable them to control fans and activate heating or cooling stages as needed for each unit. After successfully establishing communication and initial control functions, my focus has shifted to optimizing the control of multiple cooling or heating stages. The current setup has a five-minute delay between stages, but I am seeking more advanced and efficient control methods. As someone with limited experience in HVAC control outside of this particular project, I am curious about how a professional Building Management System handles stage control. Unfortunately, I have not come across typical or exemplary control algorithms in my research online. Based on my understanding, I believe that utilizing fewer stages for longer durations is generally more energy-efficient compared to shorter cycles with more stages. This will be my primary objective, unless I discover more effective approaches through further research. I have started by monitoring the performance of a non-VFD AC unit and have observed that one cooling stage was adequate until the temperature rose significantly in the afternoon. By activating a second stage, I was able to quickly achieve the desired temperature before the compressors cycled off. I have also identified some potential issues with the temperature probes and will address them accordingly. In terms of control logic, I have devised a preliminary plan that involves enabling additional stages after a delay if the temperature deviates from the setpoint beyond the hysteresis range. I am considering implementing a timeout feature to activate another stage if the temperature remains stable but does not reach the cutoff point. For units equipped with VFDs for heating and/or cooling, I am exploring specific strategies to optimize their performance. It may be beneficial to establish a minimum speed requirement that adjusts according to the number of stages in operation. At this stage, my focus has been on cooling operations, with plans to address heating functionalities as the colder months approach. I welcome any insights or suggestions from experienced individuals in this field. Thank you for your attention and support.
Considering consulting with a HVAC specialist to determine the optimal stage control method for maximizing efficiency and minimizing wear on your specific equipment. Additionally, your slopes and slope adjustments could benefit from utilizing a built-in PID control system.
Hysteresis is a concept that plays a crucial role in various systems, yet its application in logic remains unclear. The logic presented focuses on increasing the number of operational stages, raising the question of what factors lead to a reduction in the stage count.
In the image Trend4hr.jpg (also known as Trent25hr.jpg but clearer in Trend4hr), at around 15:34, the temperature of the (PV?) surpasses SP+Hysteresis (calculated as 71+1.5=72.5?), with a positive Slope10. It seems that the 20-minute timer has elapsed, resulting in an increase in the number of active stages from 1 to 2. However, by about 15:38, although the temperature has slightly decreased, it remains above SP+Hysteresis, not falling below 71. Surprisingly, the number of active stages drops from 2 to 0. What might have caused this change? Fast forward to around 15:45, the temperature rises above SP+H, with Slope10 staying positive. Despite this, why does it take more than 20 minutes, until at least 16:15, for one stage to restart?
This information could prove to be beneficial for those seeking assistance.
Apologies for the confusion, I am currently away from my laptop. You can search for CodeSys HVAC library, as well as Twincat3 and Ecostruxurr Machine Expert libraries. These libraries contain valuable information on HVAC functions and algorithms, although they do not provide actual code samples. Their descriptions are usually detailed and informative for anyone in the HVAC industry seeking to optimize their systems.
Hi there, my hat's off to the approach you're taking to optimize this system. As someone working in the HVAC field, I appreciate the diligent analysis you're putting into this task. Your focus on trying to maintain fewer stages for longer durations is generally spot on regarding energy efficiency. However, don't forget to consider peaks in energy usage. During peak hours, your electricity costs could spike, making short, numerous stages more cost-effective. For your VFD units, remember that while minimum speed requirements can be beneficial, this can put more wear on the units. Also, consider investing in better quality temperature sensors if the current ones are causing issues; accurate readings are crucial to efficient control algorithms. Lastly, look into predictive or adaptive control algorithms, which account for upcoming weather changes to optimize system performance. You're on the right track. Keep up the good work!
This sounds like a complex yet gratifying project you have on your hands. From what I understand, your strategy is headed in the right direction. Longer, fewer stages generally yield better energy efficiencies than short, rapid-cycling ones. During my stint in building management, optimizing these stages involved a lot of trial and error, so it's key to be patient. Also, regarding your VFDs, implementing a minimum rpm requirement that can be modulated according to stage requirements seems like a solid strategy. For the heating units, remember that maintaining a balance between unit utilization and energy efficiency can be a little tricky, so start planning your approach in advance. Best of luck!
It sounds like you're making great strides in optimizing your BMS! The approach you've taken with monitoring performance and adjusting based on real-time conditions is spot on. For your cooling stages, consider implementing more advanced control strategies like predictive control, which uses weather forecasts to adjust your HVAC operations proactively. Also, integrating a PID control loop could help fine-tune the temperature response more dynamically, reducing that lag time between stages. For the VFDs, experimenting with ramp rates can give you smoother transitions and improved efficiency. Lastly, don’t forget to regularly validate the accuracy of your temperature sensors, as even small discrepancies can lead to significant inefficiencies! Good luck with your project!
Hey there! It sounds like you're making some solid progress with the Building Management System. Given your observations, I’d recommend looking into more dynamic control algorithms like PID (Proportional-Integral-Derivative) or Model Predictive Control (MPC). They can help optimize stage activation based on real-time data rather than fixed delays. For instance, PID could allow for finer control while minimizing temperature fluctuations, which should enhance overall efficiency. Also, integrating feedback from your temperature probes into the system logic might help in addressing those fluctuations you’ve noticed too—good catch there! Keep experimenting, and don’t hesitate to share your findings; it’s a learning journey for all of us!
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Answer: - The BMS consists of a ControlLogix main unit with wireless communication to Micro820 units located on each roof. The Micro820 units are equipped with temperature sensors to control fans and activate heating or cooling stages.
Answer: - Currently, there is a five-minute delay between stages in the HVAC system. The aim of optimization is to find more advanced and efficient control methods for managing multiple cooling or heating stages.
Answer: - The focus is on utilizing fewer stages for longer durations as it is believed to be more energy-efficient compared to shorter cycles with more stages.
Answer: - One strategy being explored is to establish a minimum speed requirement for VFDs that adjusts according to the number of stages in operation.
Answer: - The preliminary plan involves enabling additional stages after a delay if the temperature deviates from the setpoint beyond the hysteresis range. Additionally, a timeout feature is being considered to activate another stage if the temperature remains stable but
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