Control of Peaking Problems

PEAK-CLIPPER

Low Cost Seasonal Peak Reduction

The Dencor PEAK-CLIPPER provides a simple, reliable, and low-cost solution to seasonal peaking problems. It reduces both system-wide and localized peaks. To reduce summer peaks it duty-cycles air conditioners at selected times during unusually hot days. Winter peaks may be reduced by controlling heat pump compressors or electric furnaces on unusually cold days. Water heaters can also be controlled during both seasons. The PEAK-CLIPPER makes it easy to use the historical time and temperature conditions during past demand peaks as guidelines to reduce future peaks.

Simple: The PEAK-CLIPPER is small and easily mounts directly on the compressor unit. Only three wires need to be connected. Installation or maintenance of a communication system is not required for PEAKCLIPPER use. If a communication system is in place, the PEAK-CLIPPER may be used with the communications system for increased demand reduction by using the Adaptive Cycling capability of the PEAKCLIPPER.

PEAK-CLIPPER Specifications:

Power: 24 Vac, ą15%, 60 Hz., 1.0 Watt Standby, 0.5 Watts off cycle

Contact: 3 Amperes at 24 Vac

ON-Delay: 30 Seconds (ą20%)

Cycle Time: 10 Min. to 4 Hours

Off-Time: 1% to 100% of cycle

Activation Temperature: 70° F to 110° F (ą2° F)

Differential: 3° F to 30° F (ą1° F)

Battery Life: 10 Years minimum design life

Operation: -20° F to 160° F

Packaging: White, 4.25"H x 3.6"W x 1.9"D, surface mount polycarbonate thermoplastic enclosure with provision for utility seal.

Weight: 5 oz. packaged

Patent Pending

Model WHCM Water Heater Control Module Specifications:

Size: 6"H x 4"W x 2"D

Packaging: Surface mount polycarbonate thermoplastic enclosure with 3/4" threaded nipple.

Weight: 3 pounds packaged

Voltage: 115 Vac, ą15%, 60 Hz

Power: 6 Watts Max

Contact: 24 Amps, 120/240 Vac

Specifications subject to change without notice

Low Cost: The PEAK-CLIPPER unit cost is low. It is the
lowest cost method of peak demand reduction. The benefits are similar to those of direct load control without the large investment required for a communication system. Utility savings begin with the first unit installed and increase in direct proportion to the number of units installed.

Targeted Demand Reduction: Control action is limited t the specific times-of-day, temperature range, and season when demand peaks occur. The PEAK-CLIPPER controls only when control is needed.

Easy to Operate: Choose the settings, Dencor preloads them and the PEAK-CLIPPER does the rest. It remembers to change its operation from summer to winter, if desired, and considers daylight savings changes, holidays, and weekends. Its long memory and quartz timing accuracy means it doesn't have to be reset each season.

Maximum Customer Comfort: Carefully targeted control periods minimize the duration of control. Customers have full use of the controlled load most of the time so they accept the PEAK-CLIPPER. They know control is determined by time and temperature so they can easily predict when they are likely to be controlled. This makes it easy for customers to adapt to the occasional operation of the PEAK-CLIPPER.

Simple Field Changes: The PEAK-CLIPPER permits both factory and field selection of the time and temperature parameters as well as the off-time percentage used. This makes it easy to implement future changes in utility programs. A lap-top computer may be used on site to update parameters or log operational data in seconds.

Reduces Cold-Load Pickup: The PEAK-CLIPPER provides a 30-second delay before allowing loads to come on after an outage. This makes it easier to re-energize the lines. Uncontrolled loads can power-up and stabilize before loads controlled by the PEAK-CLIPPER start.

Reduction Continues After Power Outage: Compressor cycling is truly randomized by the operation of the PEAK-CLIPPER. It remembers where it is in the control cycle at the time of a power outage. After power is restored, the PEAKCLIPPER waits for 30 seconds and then continues the cycle where it stopped when the outage occurred. Thus, if a 25% off-time is used, then 25% of the controlled loads will be in the off-cycle at the time of an outage. When power is restored, these loads will remain off to complete their off-cycle.

How the PEAK-CLIPPER Works

The time and temperature conditions which cause peak demands are used to establish an activation temperature and a control period. The PEAK-CLIPPER senses the outdoor air temperature. When the air temperature is above the selected activation temperature during a control period, the
PEAK-CLIPPER keeps the compressor off for a portion of the time. When the temperature drops a specified amount below the activation temperature or the time moves out of the control period, the PEAK-CLIPPER ceases its control. For example, it can keep the compressor off 25% of the time when the temperature rises above 95oF and has not dropped below 90oF between 4 p.m. and 8 p.m. from June 15th through September 15th except on weekends and holidays.

The PEAK-CLIPPER may be set to reduce the activation temperature each day when several days of hot weather occur in sequence. This helps reduce the high demands associated with the third-hot-day peaking phenomenon.

Compensates for Oversized Air Conditioners: Oversized air conditioners typically do not run continuously even on the hottest days. The ACT-21 and ACT-30 PEAK-CLIPPERS can monitor the operation of an air conditioner to determine the natural operating cycle of the air conditioner and then adjust the control cycle off-time to assure the desired reduction in operation. PEAK-CLIPPERS can operate in three modes as follows:

Mode 0: operation is that of a fixed percentage off-time per control cycle for all cycles. For example, a 25% reduction target would yield 7.5 minutes off during all 30-minute control cycles.

Mode 1: is adaptive operation where the off-time is automatically adjusted to reduce the operation of the compressor by a selected percentage of its natural run-time during each control cycle. For example, to obtain a 25% reduction in operation for an oversized compressor which is naturally on for 20 minutes out of a 30-minute period, the PEAKCLIPPER will automatically adjust the cycle off-time to keep the compressor off for 15 minutes out of each 30-minute period.

Mode 2: is adaptive operation where the off-time is automatically adjusted to reduce the actual kW demand of a compressor by a selected percentage of its full load kW demand during each control cycle. Thus, a 4 kW compressor selected to be controlled at 25% would automatically be cycled at a rate to make its average demand 3 kW.

Works with all Compressors: Some compressors have a 5-minute turn-on delay. For these compressors, a shorter off-time is needed. To correct for the 5 minute delay, the PEAKCLIPPER has a jumper plug to make it easy to shorten the off-time by 5 minutes when needed.

Discourages Tampering: Once started, the duty-cycle period is completed. Even temporarily cooling the PEAK-CLIPPER will not immediately halt the cycling operation. This delay discourages interference by customers. The PEAK-CLIPPER also gathers data to monitor system operation and help detect tampering. These items can include:

Minimal Impact on Thermostat: Low power requirements minimize the effect on the thermostat anticipator circuit. The PEAK-CLIPPER requires only one Watt during standby and 0.5 Watts during the off-cycle.

Easy to Install: Installation is simple as can be seen in the Wiring Diagram. Mount the PEAK-CLIPPER on the compressor unit. Then break the yellow control wire from the thermostat to the contactor coil. Connect the two ends of the yellow wire to the white and red wires from the PEAK- CLIPPER (polarity is not important). Connect the green PEAK-CLIPPER wire to the 24 Vac common point of the air conditioner. Check the operation. This takes only a few minutes. The small size of the module makes it easy to position.

Winter Peak Reduction: Special versions of the PEAK-CLIPPER are available for winter peak demand reduction. The operation for winter peak reduction is similar to that for summer peak reduction except the activation temperature is set below the deactivation temperature. Either heat pump compressors or electric furnaces can be controlled.

Water Heater Control: An optional Water Heater Control Module (WHCM) permits low-cost control of a water heater. The control period for the water heater can be defined independently from that of the air conditioner when using the ACT-20. A three (or four if the override option is used) conductor low voltage Class 2 cable is all that is needed between the PEAKCLIPPER and the WHCM. The WHCM is Listed by Underwriters Laboratory and approved by the Canadian Standards Association. The WHCM provides several benefits:

Versatile Control Strategy: Both time and temperature conditions determine control periods. Time and temperature ranges can be used either simultaneously or separately. They are independently specified for each load.

Optical Interface: An infra-red optical port permits two-way data transmission with the PEAKCLIPPER. This permits gathering of data collected by the PEAK-CLIPPER as well as a simple, high speed change of parameters defining the control strategy.

Light Tells Operating Status: A two-color light displays red, green, or blinking to show the status of the controlled load.

Model D-20 Programmer/Monitor: All units are pre-set at the factory to specifications selected by the utility. All time and temperature settings can be monitored or changed in the field with the D-20 battery-powered programmer. The programmer powers the PEAKCLIPPER for testing or setting changes even if the compressor is not running. Since the programming port is outdoors, testing or programming can be done even if the customer is not home.

Model HH-20 Loader: The time of day or new time period and temperature specifications may be loaded in a few seconds with the push of a button when using the hand-held Model HH-20 Loader.

Lap Top Computer Interface: The Model LTC Lap Top Computer interface system may be used to quickly interrogate or change settings of the PEAK-CLIPPER. Several operational programs may be stored in data files on the disk drive and selected when desired for insertion in the PEAK-CLIPPER. Likewise, the data logged by the PEAKCLIPPER may be retrieved to disk files for later evaluation and printing.

Reliable Memory: The PEAK-CLIPPER has a modern electronic battery backed-up memory module. This keeps the time for up to 10 years or more of continuous power outage. The time and temperature settings and thirty years of holidays are stored in EERAM which will keep the values for 20 years without power.

Reliable: Solid state circuits provide extended years of service. Each PEAK-CLIPPER is performance tested before shipment. Dencor provides a one-year limited warranty for all parts.

This model has fixed compressor cycling time, winter and summer compressor control operation, winter and summer hot water heater control options.

This model has adaptive air conditioner cycling modes, winter and summer compressor control operation, winter and summer hot water heater control options.

This model has adaptive air conditioner cycling modes and water heater control for April through October where activation temperatures may be selected for each of the 7 months. It is primarily used for summer peaking when the utility is billed monthly for demand peaks.

Dencor is committed to meeting the special requirements of utilities for their custom control needs. Many options are available for specific installation programs. Call Dencor with your requirements and let us quote on equipment to meet your special needs.