BAS Point Trend Data Guidance

Transcription

1 BAS Point Trend Data Guidance Rev. 3, January 2018

2 Introduction The Building Automation System (BAS also, referred to as a DDC system, or a Direct Digital Control system) at your building has been set-up for Historical Trend Data collection and you are struggling to understand how to access the information that has been collected. You ve been left with the impression that the trending has been set-up as specified for your building, but amongst all the other pressing daily issues at your facility you really have not had the opportunity to fully explore and become familiar with all the BAS training modules. This is one of many common first impressions that the complexity of a BAS can have on a Building Engineer. A good practice to keep in mind when stepping up to the initial challenges of a BAS is to avoid the trap of becoming intimidated by the complexity of the overall system. You should instead focus your efforts towards working through any particular single problem, or exercise, one step at a time and then build upon as many small successes as possible until the bigger picture begins to show through. If you find any of those initial small steps to be not forthcoming, seek out support from a qualified BAS professional who is well acquainted with your particular system and can walk you through the initial hurdles so you can get the results out of the BAS you were looking for (one small step at a time). Another good practice is to build an archive of electronic documents that include screen captures and written descriptions of the various steps observed to be taken by BAS professionals for future reference of any particular BAS task. Trend data from various energy consuming mechanical and electrical systems connected to a BAS can provide building operators and commissioners with valuable feed-back on how efficiently and effectively these systems are operating in a building. Generally, the first use for BAS system historical trend data is to track and confirm specified equipment operations for BAS start-up and commissioning crews. After the building systems have been commissioned and passed onto the building operators, the trend data collection programming used for the start-up and commissioning of the building are commonly left enabled and in-use, but not necessarily setup to fully benefit the building operator s ongoing use. Further opportunities to identify additional building energy performance and comfort improvements, such as set-point and programming adjustments, can be revealed through strategic use and analysis of BAS historical trend data. In order for these opportunities to become apparent, the BAS trend data collection programming may require some adjustments to how system parameters being targeted for improvements are captured and displayed. Any modifications to the trend data collection programming should be approached with good planning, documentation and implementation practices to avoid any unnecessary system downtime or disruptions due to overextension of available system resources. If your operating staff do not have training or experience suitable for modifying your particular BAS, then support from qualified personnel familiar with the installed BAS for the building should be engaged to implement specific changes required for the trend data collection and any subsequent programing revisions designed to bring about the targeted improvements initially considered. The target audiences for this document are building operators relatively new to BAS s or experienced professionals interested in some best-practice tips for analysis and use of BAS Trended Data. This guide will offer assistance in identifying control points that would be good candidates for inclusion in historical trend data collections. A Trending Plan, as outlined in a companion document, is another recommended first step in this process and should be completed as part of a responsible planning process prior to making any changes to existing BAS trend definitions or programming. Where building operators lack adequate experience to plan or adjust BAS Point Trend parameters, it is strongly recommended that qualified individuals are to be engaged in this process as implementers, trainers or whatever combination will result in the best possible engagement of the building operator so that the desired operational results can be achieved. Page 2 of 15

3 Table of Contents Introduction... 2 Trend Data Guidelines and Recommendations... 4 Occupied/ Un-Occupied Zone Scheduling Control... 4 Occupied/ Un-Occupied Scheduling Trend Analysis... 5 Ventilation Unit Heating and Cooling Control... 6 Ventilation Unit Heating and Cooling Trend Analysis... 7 Ventilation Unit Mixed Air and Economizer Control... 8 Ventilation Unit Mixed Air and Economizer Trend Analysis... 8 Supply Air Temperature Control Supply Air Temperature Trend Analysis Supply Air Static Pressure Control Supply Air Static Pressure Trend Analysis Zone Terminal Unit Control Zone Terminal Unit Trend Analysis Page 3 of 15

4 Trend Data Guidelines and Recommendations The following are a collection of common building energy saving opportunities where strategic use of historical or archived trending results from a Building Automation System (or BAS system) can be useful in providing clues to uncover building performance energy robbing issues: Occupied/ Un-Occupied Zone Scheduling Control: a. Potential issues to look for: Are both night heating and cooling set-back schedules in place and enabled for all building zones during unoccupied time periods through the week and on weekends? Can equipment cycling during unoccupied time periods be reduced to save energy? Are unoccupied temperature, humidity and static pressure measured values providing the greatest energy saving results while maintaining reasonable control and expectations for the areas served? Can primary HVAC equipment (fans, etc.) stop or have air flow reduced while still maintaining reasonable control during unoccupied, and possibly occupied, time periods. Can secondary HVAC equipment (pumps, boilers, chillers, etc.) be stopped, cycled or can the flow through them be reduced during unoccupied, and possibly occupied, time periods while maintaining nominal building HVAC requirements? Do all digital VAV and other terminal equipment controllers have unoccupied modes enabled and are all set-back air flow and heat/cool set-points in use? Pneumatic controlled devices: i. for day-night thermostats, is the control supply air pressure resetting to initiate the night set-back and day occupied room temperature control setpoints? ii. are the pneumatic control devices, controllers, thermostats being calibrated regularly (annually or bi-annually) for the best possible operating efficiency? iii. are all the control valves and damper actuators fully closing when they are commanded to close? b. Recommended control points to be trended over time: Occupancy mode point or fan systems to reasonably demonstrate occupancy; Secondary equipment on/off control points, set-point or resulting fluid temperature, as indicative of equipment use, as available; For a reasonable sample of zones (the larger the sample size the better): i) room temperature, humidity and static pressure, as available; ii) VAV air flow, reheat control valve position, rad or convector control valve position, electric baseboard on/off control, as available Page 4 of 15

5 Occupied/ Un-Occupied Scheduling Trend Analysis: a. Confirm that room/zone temperatures are allowed to drop to unoccupied heating setpoints or rise to unoccupied cooling set-points before any equipment is used in the unoccupied mode to either heat or cool the space (i.e. equipment used = open a heating/ cooling control valve, open a VAV box, start a fan, etc.). Reasonable set-back temperature ranges typically fall within a 3 to 6 C range of the occupied room/ zone temperature set-point 1 : i) reasonable winter months unoccupied set-back zone temperatures settings range between 19 C to 16 C and ii) reasonable summer months unoccupied set-back zone temperatures settings range between: 25 C to 28 C. b. Confirm that all humidification, cooling and gas-fired or electric heating systems in forced air ventilation systems are turned off when the fan systems are stopped (this should be obvious, but there is good value in confirming all these systems are actually not operating when the fans are stopped). c. For hydronic heating systems where the fans are stopped when the outdoor air temperature is less than 0 C, confirm that the fan s mixed air plenum temperature is no warmer than is reasonable to keep all components in the mixed air plenum from being damaged due to cold conditions (5 C is generally recommended). For glycol filled systems, and only if you have high confidence that adequate glycol concentration exists in the systems to protect the equipment from freezing, the glycol heating control valve can be fully closed or by-passed from the heat source. d. Confirm that duct and room static pressure sensors for all fan systems indicate nominally 0 Pa when the fans are off. Fan, duct or space static pressure measuring more than 0 Pa when the fan systems are commanded off should be investigated and either corrected to indicate an accurate value and/or confirmed that the fan is actually off. In the event that any duct static pressure sensors are indicating values more than +/- 20% from 0 Pa when the fan systems are confirmed to be off and there are no naturally occurring static pressure generating sources or other fan systems influencing the sensors, then the sensor should be recalibrated. If the pressure cannot be recalibrated with a reasonable level of confidence, then it should be replaced. 1..research from the Canadian Centre for Housing Technology shows that winter setbacks for houses tested would result in heating cost savings of five to fifteen percent. The highest savings came with a setback of 6 C (11 F) [ this roughly translates into 2.5% saving per degree Celsius & 0.7% per degree Fahrenheit ] Source: Canadian Mortgage and Housing Corporation Page 5 of 15

6 Ventilation Unit Heating and Cooling Control: a. Potential opportunities to look for: Is the amount of outdoor air that is being conditioned (i.e. heated, cooled and humidified) to provide good air quality in the building reasonable for the building population or could it be reduced while maintaining acceptable CO 2 levels 2 in the building? Are heating and cooling systems over-lapping each other, i.e. is simultaneous heating and cooling occurring (Do the heating and cooling systems have individually controlled thermostats - What are their settings - Do they overlap)? Can the supply air temperature be reset up or down to reduce mechanical cooling or heating load? Can the supply air temperature become so cold with mechanical cooling use that the zone reheats are needed to temper the supply air to maintain comfortable zone temperatures? Is the mixed air system being controlled to coincide with the supply air temperature control set-point to minimize mechanical heating and cooling loads? Is the mixed air system(s) reverting from free cooling to minimum damper position(s) when the comparison between the outdoor air and the return temperatures (or enthalpies) indicate that the outdoor air can no longer effectively mix with the return air to provide suitable cooling for the space being conditioned? b. Recommended control points to be trended over time with similar trend definitions when assessing a ventilation unit s heating and cooling control: Mixed air temperature; Mixed air temperature set-point; Outdoor air temperature; Outdoor air humidity (as available); Outdoor air CO 2 (as available); Outdoor air enthalpy (for enthalpy based economizer control); Return or Building air enthalpy (for enthalpy based economizer control); Outdoor air flow (as available); Differential pressure across the outdoor air damper as an indication of the amount of fresh air being drawn into the mixed air stream, as available; Reheat control valve positions; Heating & Cooling Lock-Out values and representative heating and cooling system operational values; Demand Control Ventilation (DCV) CO 2 control reference - where more than one CO 2 sensors are used to calculate the space reference value (the maximum measured CO 2 sensor value is the preferred value to be used for the space reference), all values should be trended; All control devices affecting the mixed air temperature control and supply air temperature control (i.e. mixed air dampers, minimum position outdoor air damper, fresh air injection fan, preheat control valve, heating control valve, cooling control valve, dehumidification control cycles, etc.); 2 1,000 PPM can be interpreted as a guideline for a limiting control set-point of space air quality control towards a surrogate level of odor causing components generated from human activity that may not be acceptable for human comfort of air quality: Summary of ASHRAE s position on Carbon Dioxide (CO 2 ) Levels in Spaces, by Stephen Petty, P.E., C.I.H. Page 6 of 15

7 Ventilation Unit Heating and Cooling Trend Analysis: a. ASHRAE Standard 62.1 defines the minimum amount of fresh required to be introduced into a building for air quality management based on building occupant population. This code defines a DCV requirement and CO 2 sensor use as a means of managing this process through matching reasonable amounts of fresh air delivery to the quantity of people and activities of this population through the various zones in a building. With changes in building population and different modes of operation that a building can go through in a day, the amount of outdoor air introduced to the HVAC system requiring conditioning (i.e. heating, cooling, filtration, humidification, etc.) tends to be a significant factor in the operating costs of a building. The use of trended values for all parameters related to outdoor air volume measurement and CO 2, where DCV control strategies are in place, are important and should be compared to ASHRAE 62 requirements to confirm the volume of outdoor air being introduced to the HVAC system in real-time is not considerably more than is required to maintain reasonably good overall air quality in the building. Annual calibration of temperature and CO2 sensors should also be completed for optimal energy performance and control, in consideration of the important role played by these devices in building HVAC systems. b. Assessing trended results for heating and cooling control devices during periods of cooling mode use will provide an opportunity to identify any inadvertent simultaneous use of both these systems. Where reheat coils are part of down-stream HVAC systems that are used to temper the supply air distribution systems during the cooling season, a better choice for tempering the cooling supply air stream might be to simply allow the temperature of the mixed air and resulting supply air to increase a little instead - by reducing the use of mechanical cooling. An energy-conservation guideline to consider for this type of system is to use a supply air temperature reset strategy that will adjust up the supply air temperature adequately so that minimal reheat is applied to mitigate the cost of simultaneous heating and cooling. Minimal use of boiler hot water should also be considered when building heating hot water is required during the cooling season. Most facility operators generally turn-off the hot water boiler systems when in the cooling mode, or generally in the summer, to prevent this scenario from occurring. c. Over-lapping heating and cooling lock-outs can occur through simple confusion or byway of inadvertent post commissioning control programming adjustments. This occurrence is best flushed-out through review of trended results for the lock-out values and compares them to specified or known expectations to confirm that the heating and cooling systems have a well-defined intermediate range where neither is in use. d. Cooling through the use of the economizer is considerably more cost effective than by using mechanical cooling equipment. The use of the economizer is typically limited by the temperature and humidity of the ambient outdoor air. Based on the specific control strategy that has been selected for the building, the more outdoor air that is introduced through the mixed air dampers before the mechanical cooling systems are enabled, the more utility energy savings can generally be realized. In drier climates, ambient dry-bulb temperatures are generally adequate for this purpose, while in climates having higher levels of humidity enthalpy content in the air is generally used. Trended values for the mixed air damper, mechanical cooling systems, outdoor air temperature and humidity to confirm economizer mode transition and mechanical system use will generally identify how efficiently these systems are interacting with each other. Page 7 of 15

8 Ventilation Unit Mixed Air and Economizer Control: a. Potential opportunities to look for: Are the motorized dampers inoperative - stuck in open or closed positions? Are motorized damper linkages or actuators disconnected or malfunctioning? Are the motorized dampers not fully closing/ faulty edge seals resulting in unwanted conditioned air leakage from the building? Is the mixed air temperature acceptably tracking the mixed air temperature setpoint? Is the mixed air temperature control erratic or unstable, over time? b. Recommended control points to be trended over time with similar trend definitions when assessing mixed air temperature control: Mixed air temperature; Mixed air temperature set-point; Outdoor air temperature; The controlled devices affecting the supply air temperature control (i.e. heating and cooling control valves, gas-fired heating reset, mixed air dampers, etc.). Ventilation Unit Mixed Air and Economizer Trend Analysis: a. Damper maintenance is important for reliable operation of mechanical systems. Annual lubrication and adjustment for full freedom of movement will pay significant dividends in energy dollar savings. Since the mixed air system handles a considerable volume of air and is essentially the first line of conditioning in most ventilation systems, it is a very influential component and warrants an appreciable level of attention. b. The importance of mixed air damper systems can easily be unappreciated and can commonly result in varying degrees of neglect and poor states of repair. Actuators, linkages, jack-shafts, damper blades etc. are all part of the mixed air system and require regular lubrication, adjustment and repair to maintain optimum control and energy efficiency of the overall system. c. Effective damper closure when the ventilation unit is stopped can be a significant factor in building energy management and is important for the protection from damage of hydronic equipment contained within the ventilation unit in extreme cold climates. Adjustment of the damper actuator to preload the outdoor air damper for good closure will result in reasonable management of energy losses through the damper assembly when closed. Damper edge seal maintenance and repair are equally important for the management of energy losses through building damper sections to prevent unnecessary energy losses when the fans systems are not in use. d. When the following guideline conditions are observed to be true, the mixed air damper control is probably operating correctly: the position of the mixed air dampers is beyond the minimum ventilation damper position and tracking in free-cooling range of control; trend data results or multiple screen print-outs indicate that the mixed air temperature and the set-point values are consistently within +/- 4% of each other; trend data results or multiple screen print-outs indicate that the mixed air damper control is not hunting or un-responsive. When mixed air dampers are either limited by a minimum ventilation position in winter conditions or reverted to a minimum position in the summer to minimize mechanical Page 8 of 15

9 cooling load, well managed mixed air temperature control cannot be expected. Since there could be situations where both heating and cooling control devices are not in use, the mixed air temperature control set-point could be the same or somehow related to the supply air temperature control. This should be taken into consideration when assessing trend results of mixed air temperature control for energy saving opportunities during free cooling modes. e. When the position of the mixed air dampers is beyond the minimum ventilation damper position and trend data displays for the mixed air temperature value and the set-point values are not within +/- 4%, this is a probable indication that loop tuning for the controlled devices or the controlled devices are in need of attention. Flat line trend data patterns from the mixed air temperature that is considerably off of the mixed air temperature set-point could suggest control device failure. Page 9 of 15

10 Supply Air Temperature Control: a. Potential opportunities to look for: Is the supply air temperature value acceptably tracking the supply air temperature set-point? Is the supply air temperature value erratic or unstable, over time? Is a supply air temperature reset schedule set up correctly and in use ( i.e. is the supply air temperature set-point fixed and manually adjusted from building occupant complaints)? Is the supply air temperature value tracking too high or too low from the supply air temperature set-point? Has the indicated supply air temperature value failed or is it indicating unrealistic values? b. Recommended control points to be trended over time with similar trend definitions when assessing supply air temperature control: Supply air temperature; Supply air temperature set-point; Mixed air temperature; Mixed air temperature set-point; The controlled devices affecting the supply air temperature control (i.e. heating and cooling control valves, gas-fired heating reset, mixed air dampers, etc.) Supply Air Temperature Trend Analysis: a. If trend data shows that the supply air temperature is consistently being maintained within +/- 4% of the set-point control values, recorded in regular time segments daily over the duration of no less than a week, then this is generally a reasonable indication that the supply air temperature control is operating acceptably, for that particular season. Similar supply air temperature control trend result assessments for each season (winter, summer, spring and fall) can be used to demonstrate that the supply air temperature control is operating acceptably overall. b. If the supply air temperature sensor values are questionable or reporting an unreasonable value, sensor calibration or replacement may be necessary. c. Where trend data for the supply air temperature and the set-point values are not within +/- 4%, this could be an indication that the BAS control loop tuning parameters or the controlled devices are in need of attention. Supply air temperature flat line trend data patterns can suggest potential control device failure while erratic trend data patterns suggest possible loop tuning control issues. d. Where the supply air temperature trended values show noticeable reduction or increase in temperature control coincident with the starting of a chiller or boiler, this could be an indication that the control valve is encountering some close-off issues and might be in need of adjustment or replacement. Page 10 of 15

11 e. Where trend data for the supply air temperature and the set-point values are not within +/- 4% and all controlled devices that impact the supply air temperature control are closed or off, investigation of any upstream controlled devices that could be affecting the supply air temperature control should be considered. These upstream controlled devices could include pre-heat control valves or the mixed air damper actuators. Where upstream devices are not the cause of this situation, control sequence programming for the supply air temperature control should be reviewed for any possible contributing issues. f. Where applicable, the addition of, or modification to, a supply air temperature reset control strategy to include programing that will provide the minimum amount of cooling required to satisfy the warmest significant zone, or zones, of a building can be an effective way of saving utility energy costs in a multi-zone building. The actual supply air temperature reset range for both cooling and heating modes can be expected to be relatively unique for each building. Ideally for cooling, the optimum supply air temperature will occur when the VAV box serving the zone having the most extreme cooling demands operates at 100% capacity while resulting in the room cooling demands being met and the room temperature being maintained at set-point. Depending on the specific VAV heating mode control strategy, a similar optimum reset supply air temperature control strategy can be determined using a similar approach to find the lowest tolerable supply air temperature that will keep the building occupants comfortable while not adding unnecessary heating load on auxiliary heating equipment. Where VAV zone systems can be trended, airflow control patterns can be monitored and compared to the supply air temperature and outdoor air temperature trends can be analyzed to work-out at a reset supply air temperature control strategy. g. A control sequence programming upgrade that uses time-steps to adjust the supply air temperature set-point up and down from VAV zone feed-back could also be considered as another option for optimizing the supply air temperature reset control strategy. Trending of the VAV zone operation and space temperatures could be used to fine tune the ratcheting rate for optimum results. Where zone feed-back control strategies are being considered, refer to the Zone Terminal Unit Control for recommended trending and observations in addition to those identified in this section. h. Sequencing of auxiliary heating and cooling equipment within each building zone with the primary cool/heat source can also present opportunities for energy utility cost saving if overlapping heating and cooling operation has been identified and can be corrected. Refer to the Zone Terminal Unit Control for recommended trending and observations in addition to those identified in this section. Page 11 of 15

12 Supply Air Static Pressure Control: a. Potential opportunities to look for: Is the supply air static pressure value acceptably tracking the supply air static pressure set-point? Is the supply air static pressure value erratic or unstable, over time? Is the supply air static pressure value tracking too high or too low from the supply air static pressure set-point? Has the indicated supply air static pressure value failed or is it indicating unrealistic values? Is the speed drive at minimum, or fan inlet vanes nearly closed, while the supply air static pressure value is higher than the supply air static pressure set-point? Is the speed drive at maximum, or fan inlet vanes fully open, while the supply air static pressure value is less than the supply air static pressure set-point? b. Recommended control points to be trended over time with similar trend definitions when assessing supply air static pressure control: Supply air static pressure; Supply air static pressure set-point; Supply air static pressure high limit (if available); Supply air static pressure high limit set-point (if available); The controlled devices affecting the supply air static pressure control (i.e. speed drive (or VFD), fan inlet vanes or dampers, modulating control dampers, by-pass VAV control box, etc.); Down-Stream terminal equipment controlled devices (i.e. VAV damper positions). Supply Air Static Pressure Trend Analysis: a. If trend data shows that the supply air static pressure is being maintained within +/- 7% of the set-point control values, recorded in regular time segments daily over the duration of no less than a week, then this is generally a reasonable indication that the supply air static pressure control is operating acceptably, for that particular season. Similar supply air static pressure control trend assessments for each season (winter, summer, spring and fall) can be used to demonstrate that the supply air static pressure control is operating acceptably overall. b. If the supply air static pressure sensor value is questionable or reporting an unreasonable value, sensor calibration or replacement may be required? c. Where trend data for the supply air static pressure value and the set-point values are not within +/- 7%, this could be an indication that the BAS control tuning parameters or the controlled devices are in need of attention. Supply air static pressure flat line trend data patterns can suggest potential control device failure while erratic trend data patterns suggest loop tuning control issues. d. Where trend data for the supply air static pressure value and the set-point values are not within 10% and the controlled device that impacts the supply air pressure is trending at its minimum value, this may be an indication that the down-stream systems are also operating at minimal values or that the ductwork is blocked by an obstruction (i.e. a closed fire damper). Where the down-stream terminal equipment systems are operating at minimum values, this could be an indication that the supply air temperature being distributed to the building from this AHU system is actually too cold for the needs of the building and that most of the zone terminal units are operating at their minimum air flow capacities to avoid overcooling the various zones spaces throughout the building. This Page 12 of 15

13 can generally be resolved by resetting the supply air temperature up in small increments until the airflow begins to recover to more reasonable values. A time-stepped adjustment program can be implemented that will increase the supply air temperature 0.5 C every 15 minutes (or some other combination of values appropriate for the size of the ventilation system) until the supply air static pressure moves to within a reasonable range. Similarly when the supply air flow is greater than reasonable values, a similar time-stepped programmed control sequence can reduce the supply air temperature until resulting air flow and/ or static pressure move to within a reasonable range. e. If trend data displays supply air static pressure values that are tracking at 10% or less than the set-point while the controlled device is trending at, or near, its maximum value, then this may be an indication that the: i) down-stream terminal equipment systems are demanding more air flow than the ventilation system is capable of delivering. This could be addressed by increasing the cooling capacity of the ventilation system by reducing the supply air temperature 0.5 C every 15 minutes (or some other combination of values appropriate for the size of the ventilation system) until the supply air static pressure rises to within a reasonable range of set-point, through a time-stepped control strategy or, ii) high-limit static control strategy could be in effect and may be over-riding the controlling duct static pressure sensor. In the event that adjustment is being considered to the high-limit set-point, careful analysis of trend data and ventilation system parameters is recommended before making any changes are made to establish whether the system can handle any additional static pressure without resulting in damage. Page 13 of 15

14 Zone Terminal Unit Control: a. Potential opportunities to look for: Is a zone terminal unit located in an interior (or exterior) zone delivering more heated or cooled ventilation air than other similar units in the same zone? Is the space temperature in any terminal unit zones more than 5% higher or lower than the temperature set-point? Are there any building zones that have unique heating or cooling demand requirements that can be significantly influencing the source/ primary AHU heating or cooling systems adversely? Are any zones out of control and oscillating between heating and cooling modes? b. Minimum recommended representative zones to consider for trending in a building: Floors with less than 8 zones per floor = trend all zones per floor; Floors with more than 8 zones per floor = trend a minimum of 8 zones per floor (where practical: select 4 exterior zones representative of each building face direction (i.e. N., E., S. & W.) and 4 interior zones). c. Minimum recommended representative floor counts to consider for trending in a building: Less than 4 floors = trend all floors; 4 floors, or more = trend every other floor; 20 floors, or more = trend every third floor; d. Generally, when analyzing trend data for energy saving opportunities, give special consideration to the following: i. comfort complaint zones; ii. focus on any Interior zones with low heating and cooling demand that may be unnecessarily skewing any feed-back control from primary building requirements (i.e. unoccupied, reduced occupancy, janitor & storage rooms) where no feed-back control is in use to influence the primary building heating and cooling systems these areas can be disregarded from any programming and trending; e. Recommended control points to be trended over time with similar trend definitions when assessing zone control (trend as many as possible from the following): Occupancy and Temporary Occupancy (as available) Room temperature Room temperature set-point; Cooling and/ or Heating Loop or control Device; Air flow and air flow set-point (as available); Fan status and command (as available). Page 14 of 15

15 Zone Terminal Unit Trend Analysis: a. Review results for the heating and cooling control devices in all trended zones for general comparison and identify those zone having noticeably greater heating and/or cooling demand. Investigate and take corrective action for any set-point adjustment or other factors that may cause increased demand for these zones. b. Review results of all building space temperatures in all trended zones and identify any values observed to be in excess of +/- 2.5 C from set-point. Confirm the heating and cooling control demand values are being correctly applied to the control device. Confirm the control device is fully operational and that when commanded to close or be off that it actually does fully close or stop. c. Review temperature results for all electrical service rooms, and other similar conditioned building spaces, in the building and adjust temperature set-points to appropriate values for the intended purpose of the room. Many buildings have storage or electrical rooms that have different purposes than most other rooms and frequently these rooms tend to be handled similar to other rooms unnecessarily and in some cases dictate heating or cooling demands of primary AHU systems. An example of this is an electrical room that has a sizable concentration of heat generating equipment with higher tolerances for warmer temperatures than most other spaces in a building being maintained at nominal comfort levels unnecessarily in this scenario where a control feed-back strategy is in use the supply air temperature reset control set-point could be unnecessarily driven down to its coldest possible value to cool the electrical room. Most electrical rooms can generally operate up to 27 C (80 F) without any adverse effects to the equipment contained in the room while typical building occupant comfort is obtained in a temperature range of 21.5 C to 23.5 C (70.7 F to 74.3 F) 3. d. Review all trended temperature results for erratic swings in values. Room temperatures in controlled conditioned spaces do not typically vary more than 1 C in 15 minute time spans in stable nominal operating conditions. Where erratic temperature swings are observed, temperature sensors, control devices, controllers and possibly external programming are all potential sources that should be considered and investigated. Temperature sensor placement should also be reviewed to confirm that the room temperature control is not being adversely affected by direct sunlight or other potential heat sources (i.e. office photo copiers) that could contribute to false, potentially erratic, temperature indication for the space. 3..research from the Canadian Centre for Housing Technology shows that winter setbacks for houses tested would result in heating cost savings of five to fifteen percent. The highest savings came with a setback of 6 C (11 F) [ this roughly translates into 2.5% saving per degree Celsius & 0.7% per degree Fahrenheit ] Source: Canadian Mortgage and Housing Corporation Page 15 of 15