### Setpoints Use setpoints to set temperature values that control the HVAC equipment. The WebCTRL® interface shows the color green when a zone is within the desired temperature range determined by the heating and cooling setpoints. Programmed setpoints are set and changed by operators. See To change programmed setpoints. Effective setpoints reflect the impact of other system conditions on the programmed setpoints, such as setpoint adjustments, demand reduction adjustments, and hysteresis. Effective setpoints control the equipment. Besides manually adjusting setpoints, you can use the following cost-saving strategies to adjust setpoints automatically: Optimal Start Demand Control Setpoint Optimization
Click for details below To change programmed setpoints Optimal Start Demand Control Setpoint Optimization
#### To change programmed setpoints Navigate to a setpoint control in one of the following places: The zone temperature section of a Properties page The setpoint microblock pop-up on a Logic page A Graphics page (Click a setpoint trend graph control to access the editable setpoint bar.) On a programmed setpoint bar, click the segment or the gap between segments you want to change. Type new values in the Heating and Cooling fields. TIP You can click and drag a segment or a gap between segments to change setpoints. Click Accept.
#### Optimal Start Optimal Start gradually moves the unoccupied setpoints toward the occupied setpoints as the occupied time approaches. The actual equation that a controller uses to calculate Optimal Start is nonlinear. An approximation of the equation is shown below. Refining Optimal Start saves energy in the following ways: Removing guesswork from preheating or precooling zones Ensuring that zones reach the ideal comfort range just as people arrive Preventing equipment from running unnecessarily during unoccupied periods You can adjust the Optimal Start routine in the control program's setpoint microblock. On the Geographic tree, select the equipment that you want to change. Click Properties. Adjust the following fields located below the setpoint graph.
Field | Notes
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Heating Capacity Cooling Capacity | The maximum rate (in °F/hr) that the zone temperature could be changed by heating or cooling if the outside temperature were 65°F. For example, if it takes 2 hours for a zone to warm up from 65°F to 72°F, the heating capacity is 3.5°F/hr NOTE Use 5°/hr as a starting point if you are unsure of actual capacities.
Heating Design Temp Cooling Design Temp | The most extreme outside winter and summer temperatures at which the equipment must run 100% of the time to maintain the zone temperature at a comfortable level. ASHRAE determines design temperatures based on the geographic location of the building.
NOTE A Setpoint microblock with Learning Adaptive Optimal Start functionality automatically adjusts the heating and cooling capacities to optimize efficiency. Learning Adaptive Optimal Start If you are using the Learning Adaptive Optimal Start feature and a zone does not reach the ideal temperature range by the time occupancy begins or reaches it too soon, then the heating or cooling capacities of the equipment are automatically adjusted up or down for the next unoccupied period. When the Learning Adaptive Optimal Start routine runs, adjustments are made based on the color that is achieved when occupancy begins. Adjustment amounts are defined for thermographic colors in the control program's setpoint microblock. For example, the heating capacity for a zone is 5° per hour. When the zone becomes occupied, the zone temperature is 1° below the occupied setpoint, indicating a need for additional heat. Because the zone temperature was low by 1°, the learned heating capacity will be decreased by the Less than Heating setpoint value. If the value is 0.06, the learned heating capacity will be adjusted to 4.94° for the next optimal start period. The setpoint adjustment will begin sooner in the next unoccupied period. If you need to change the adjustment values in the Learning Adaptive Optimal Start routine: On the Geographic tree, select the equipment that you want to change. Click Properties. Adjust the color fields between the Zone Setpoints graph and the Effective Setpoints graph. CAUTION When using Learning Adaptive Optimal Start, be sure that all equipment is properly maintained so that your system does not “learn” to compensate for dirty filters or loose fan belts. TIP After your system has run for at least a year, you may want to turn off learning in your control program, and change the Heating Capacity and Cooling Capacity in your control program to match the learned heating or cooling capacity shown on the Properties page.
Fields | Notes
--- | ---
Color fields | The amount of adjustment the system makes for the color that is achieved at the beginning of occupancy.
Learned cooling and heating capacity | The rate (in °F/hr) that the zone temperature can change by heating or cooling at an outside temperature of 65°F.
Actual or adjusted capacity | The actual heating or cooling capacity of the equipment at an outside temperature of 65°F.
#### Demand Control Demand Control is a cost-saving strategy that saves energy while maintaining comfort in the following ways: Controlling energy use to avoid peak demand, ratchet, or time of use utility charges Maintaining ventilation at relaxed setpoints rather than shutting down equipment (as with load shedding or duty cycling) Before you can use Demand Control effectively, you must: Obtain details regarding past energy usage and peak demand, ratchet, and time of use charges from your energy provider. Understand the demand profiles of the zones you are controlling. Demand Control can be customized at the zone level. For example, you may relax the setpoints in some zones, like break rooms and closets, by a few degrees, but you may not want to relax setpoints in computer rooms at all. A Setpoint microblock that has the Demand Limiting enabled uses a demand control strategy to conserve energy by relaxing setpoints as the demand level rises. In the EIKON® application, you define the amount that setpoints will be adjusted or relaxed based on the demand level. To define Demand Control properties On the Geographic or Network tree, select the electric meter. On the Properties page, expand the Demand Level Parameters section. Type the Start and End time to define the time period that you want demand control to be in effect for this zone. Type kilowatts per hour (kW/hr) in the Level columns to define the amount of power that the demand must exceed before the WebCTRL® system calls for a higher demand level. NOTE Levels are defined in the electric meter control program in the EIKON® application. You can test the Demand Levels by locking the meter to a value. In the example below, during Period 4, defined as 12:00 (noon) to 16:00 (4:00 p.m.), if the demand exceeds 800 kW/hr, the WebCTRL® system will use Demand Level 1 setpoints. If the demand exceeds 1000 kW/hr, the WebCTRL® system will use Demand Level 2 level setpoints and so on.
#### Setpoint Optimization Setpoint Optimization, also known as Trim and Respond, saves energy by calculating the setpoint of a piece of equipment based on the number of heating or cooling requests it receives from other equipment. You must put a Setpoint Optimization microblock in a control program to receive Total, Average, Minimum, or Maximum microblock outputs from linked equipment.