Initial Demonstration

After the TTR programs and power reading equipment were installed and verified, an initial demonstration was conducted to ensure the parameters used such as TM, RP and Step Timer values were adequate. During this time, functional modes alternated daily between TTR and FSP or TTR and TR. Table 3.2 provides the initial parameters and the functional mode comparisons and Table 3.3 provides temperature control strategies and setpoints used.

Table 3.2 Initial functional mode comparison and TTR parameters.

Site Unit Functional Mode TTR Parameters Step Timer TM1/RP1 TM2/RP2 TM3/RP3 Boone RC AHU-1 TTR FSP 0.036" 0.072" 0.108" 90 AHU-2 TTR FSP 0.030" 0.060" 0.090" 90 Des Moines MEPS AHU-1 TTR FSP 0.038" 0.076" 0.114" 60

JFHQ AHU-1 TTR FSP 0.060" 0.120" 0.180" 120 AHU-2 TTR TR 0.050" 0.100" 0.150" 120 AHU-3 TTR TR 0.060" 0.120" 0.180" 120 AHU-4 TTR FSP 0.050" 0.100" 0.150" 120 AHU-9 TTR FSP 0.040" 0.080" 0.120" 120 AHU-12 TTR FSP 0.020" 0.040" 0.060" 120 Muscatine AFRC RTU-1 TTR FSP 0.030" 0.060" 0.090" 120 RTU-3 TTR FSP 0.080" 0.160" 0.240" 120 RTU-4 TTR FSP 0.070" 0.140" 0.210" 120 Waterloo RC RTU-1 TTR FSP 0.090" 0.180" 0.270" 90

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Table 3.3 Initial temperature control strategy and static pressure setpoint limits.

Site Unit Temperature Control

TTR FSP/TR

SPmin SPmax SPmin SPmax Boone RC AHU-1 Fixed 55°F 0.40" 2.20" - 2.20"

AHU-2 Fixed 55°F 0.40" 1.70" - 1.70" Des Moines MEPS AHU-1 Reset OA 0.25" 1.40" - 1.40"

JFHQ AHU-1 Reset OA 0.50" 2.40" - 2.40" AHU-2 Reset OA 0.50" 2.00" 0.50" 2.00" AHU-3 Reset OA 0.50" 2.40" 0.50" 2.40" AHU-4 Reset OA 0.50" 2.00" - 2.00" AHU-9 Reset OA 0.20" 1.40" - 1.40" AHU-12 Reset OA 0.80" 2.70" - 2.70" Muscatine AFRC RTU-1 Fixed 55°F 0.40" 1.25" - 1.25" RTU-3 Fixed 55°F 0.40" 2.30" - 2.30" RTU-4 Fixed 55°F 0.40" 2.50" - 2.30" Waterloo RC RTU-1 Fixed 55°F 0.70" 1.60" - 1.60"

From Table 3.3, the SPmax values used during the initial demonstration vary greatly from what was discovered in the site investigation. The values first seen were from initial commissioning documents, while the values in Table 3.3 are used typically at the

recommendation of the facility managers and engineers. Many of the SPmax values have been reduced due to occupant complaints of noise, and frequent unit trips due to high static pressure alarm faults. The existing reduction of the SPmax values may inhibit any available energy savings provided by the TTR strategy.

With these parameters used for several weeks, data from initial demonstration were downloaded and analyzed. To ensure data were from normal or valid test days, a set of criteria was used to determine if a particular day’s data should be deemed valid and used for analysis:

• Normal occupancy hours – i.e. if the site normally has a 10 hour occupancy schedule, days where occupancy was switched to 24 hour occupancy in error would be ignored in

analysis. However, due to the nature of some of the facilities functions, a 24 hour occupancy schedule was used but was then returned to normal at a later time.

• Operational supply and return fan – i.e. days where a supply and/or return fan tripped for extended periods of time were ignored during analysis.

• Setpoints were not altered to negatively affect the study – i.e. days with altered static pressure setpoints reducing TTR static pressure setpoint below FSP setpoint were ignored during analysis.

• Data are full and complete – i.e. days with incomplete or missing trends of key measurements for extended periods of time were ignored during analysis.

• Functional mode switch occurred automatically at midnight – i.e. days that the functional mode had to be switched manually were ignored.

Initial Observations

Early on during the initial demonstration, instances of excessive static pressure

oscillation were present in nearly all TTR days across each site. This was largely attributed to the initial TM and RP parameters used but some instances were caused by dampers in need of repair or replacement. As such, dampers and other related equipment were repaired or replaced and parameters were adjusted to better accommodate each AHU/RTUs capabilities. Figures 3.4, 3.5, 3.6, 3.7 and 3.8 provide early examples of excessive static pressure

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Figure 3.4 Static pressure oscillation from initial TTR parameters, 5/25/2015.

Figure 3.6 Static pressure oscillation from initial TTR parameters, 7/8/2015.

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Figure 3.8 Static pressure oscillation from initial TTR parameters, 6/5/2015.

As seen in the previous figures, static pressure oscillated heavily with the initial TTR strategy. Figures 3.5 and 3.6 showed instances with large ramp ups in static pressure, and in some cases this would cause units to trip due to high static alarms. Figures 3.4, 3.7 and 3.8 provide examples of excessive static pressure oscillation that was apparent early on. To minimize these issues, adjustments were made to the TM and RP values, the summation of the TM and RP tiers and lengthening of the step timer. Table 3.4 displays the new response given for the MDP value used for the official demonstration. Tables 3.5 and 3.6 provide the TM and RP values and step timer used during the official demonstration.

Table 3.4 Refined TTR strategy used during the official demonstration.

Condition Response

If MDP > High3 SPSet = SPSet + RP3 If MDP > High2 SPSet = SPSet + RP2 If MDP > High1 SPSet = SPSet + RP1 If High1> MDP > Low1 No change

If MDP < Low1 SPSet = SPSet - TM1 If MDP < Low2 SPSet = SPSet - TM2 If MDP < Low3 SPSet = SPSet - TM3

High3>High2>High1>Low1>Low2>Low3

(suggested values 95%, 92%, 90%, 85%, 83%, 80%, respectively) MDP Maximum Damper Position (Feedback or Command Signal) SPSet Static Pressure Setpoint

TM1,2,3, RP1,2,3 Trim and response rates. All positive numbers.

Table 3.5 Functional mode comparison and TTR parameters used during official demonstration.

Site Unit Functional Mode TTR Parameters Step Timer TM1/RP1 TM2/RP2 TM3/RP3 Boone RC AHU-1 TTR FSP 0.036" 0.072" 0.108" 180 AHU-2 TTR FSP 0.030" 0.060" 0.090" 180 Des Moines MEPS AHU-1 TTR FSP 0.0380" 0.076" 0.114" 300

JFHQ AHU-1 TTR FSP 0.040" 0.080" 0.120" 300 AHU-2 TTR TR 0.025" 0.050" 0.075" 300 AHU-3 TTR TR 0.040" 0.080" 0.120" 300 AHU-4 TTR FSP 0.025" 0.050" 0.075" 300 AHU-9 TTR FSP 0.025" 0.050" 0.075" 300 AHU-12 TTR FSP 0.020" 0.040" 0.060" 300 Muscatine AFRC RTU-1 TTR FSP -0.005" -0.010" -0.015" 300 0.010" 0.020" 0.030" RTU-3 TTR FSP 0.030" 0.060" 0.090" 300 RTU-4 TTR FSP 0.028" 0.056" 0.084" 300 Waterloo RC RTU-1 TTR FSP 0.030" 0.060" 0.090" 300

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Table 3.6 Temperature control strategy and static pressure setpoints used during official demonstration.

Site Unit Temperature Control

TTR FSP/TR

SPmin SPmax SPmin SPmax Boone RC AHU-1 Fixed 55°F 0.40" 2.20" - 2.20"

AHU-2 Fixed 55°F 0.40" 1.70" - 1.70" Des Moines MEPS AHU-1 Reset OA 0.25" 1.40" - 1.40"

JFHQ AHU-1 Reset OA 0.50" 2.40" - 1.50" AHU-2 Reset OA 0.10" 1.50" 0.10" 1.50" AHU-3 Reset OA 0.50" 2.40" 0.50" 2.40" AHU-4 Reset OA 0.50" 1.80" - 1.50" AHU-9 Reset OA 0.20" 1.40" - 1.40" AHU-12 Reset OA 0.80" 1.50" - 1.50" Muscatine AFRC RTU-1 Fixed 55°F 0.40" 1.25" - 1.25" RTU-3 Fixed 55°F 0.40" 2.30" - 2.30" RTU-4 Fixed 55°F 0.40" 2.50" - 2.30" Waterloo RC RTU-1 Fixed 55°F 0.50" 1.60" - 1.60"

As shown in Tables 3.5 and 3.6, TM and RP rates for all AHUs and RTUs were reduced significantly. Along with these reductions, the SPmax and SPmin were adjusted to alleviate issues perceived early on due to excessive noise or faults from high static pressure alarms. The step timer within the TTR strategy was lengthened due to numerous observations of slow responses of the static pressure setpoint command vs static pressure.

For this study, 2 AHUs will compare the TTR and TR functional modes, while the remaining AHUs and RTUs will compare the TTR and FSP functional modes. For the a TTR and TR comparisons, temperature reset based on outside air temperature was used; for the TTR and FSP comparisons, both temperature reset based on outside air temperature and fixed temperature was used. Table 3.6 specifies which sites used a fixed supply air temperature and an outside air based reset supply air temperature.

CHAPTER 4