To start we need to define some terms for those not familiar with the process:
Coincidence Factor = (Maximum System Demand)/(Sum of Individual Maximum Demands), or the ratio of the maximum demand of a system, or part under consideration, to the sum of the individual maximum demands of the subdivisions.
Demand Factor = (Maximum Demand Load)/(Total Load Connected), or the ratio of the maximum demand on a system to the total connected load of the system.
Diversity Factor = (Sum of Individual Maximum Demands)/(Maximum System Demand) , or the reciprocal of the Coincidence Factor
Horsepower – 1hp ≈ 1 kVA
kW – Kilo Watts or 1000 Watts
kVA – kilo Volt Ampere or 1000 Volt Amps
Load Density – watts/ft2
Load Factor = (Average Load)/(Maximum Demand)
Maximum Demand – the integrated demand for a specified time interval, rather than the instantaneous or peak demand.
Load Data
Load data is a best eaten by bites. You break down this process as follows:
– Individual Loads: are those loads with one incoming service supply. This refers to usually a single structure.
– Lighting: divided by function, e.g. office, storage, mechanical and corridor. The average light levels and type of light source are determined for each area. You need to consider supplemental lighting like area floods, security lighting and lighting for special tasks. This is based on about 1 Watt/square foot (sf) from 6-8-foot candles (fc) for incandescent illumination to a high of 54-fc for high pressure sodium lights.
– Small Appliance Loads: The areas of the facility are divided by function. Office loads will pull about 0.5 to 1.5 W/sf but a machine shop can gobble up to 2.5 W/sf. Small appliances are seldom under continuous use, so peak usage is a rarity.
– Loss: A typical loss overhead of about 6% based on the maximum demand is added to the building load.
– Electrical Power Loads: Includes all loads, but not lighting and those served by general purpose outlets but do include environmental systems requirements e.g. air conditioning and heating.
– Demand & Load Factors: These can vary. This is based on the hours of usage and the division of load. These empirical loads can vary from activity to activity and vary from facility to facility within an activity. The point is that power usage is not constant for a manufacturing operation. A law or CPA firm, however, should be relatively stable.
– Load Growth: Planning should consider growth in the load. Adding new heavy power consuming equipment like AC, electric heating, electronic data processing the method of distribution should be considered and included.
– Emergency Loads: Some facilities are subject to emergency loads and include a) minimum essential load, b) emergency load for vital operations, c0 uninterruptible load.
Area Loads: These are loads that consist of groups of each facility load served by a subdivision of the electrical system. Sizing and power distribution of wiring and switches depend on the loads served.
Power Monitoring
Most of these can be determined by 30 to 90 days monitoring. Installation of the monitoring equipment can provide the actual working data from those engineering estimates the are conducted based on potential loads, rules of approximations of tables and charts as indicated by the load type obtained from equipment plates and specs. Monitoring and analysis go hand in hand providing actual operating power consumption. Timing is essential as the monitoring phase should be conducted during the historical highest use power consumption. This will allow monitoring when the system is under maximum stress.
Energy Monitoring, Power Management & More in Arvada, Aurora, Black Hawk, Boulder, Broomfield, Centennial, Cherry Hills, Commerce City, Englewood, Golden, Greenwood Village, Highlands Ranch, Lakewood, Lafayette, Littleton, Parker, Thornton, Westminster, Wheat Ridge & Greater Denver, CO | Jefferson & Gilpin County, Colorado
Power planning depends on a longish period of monitoring to be effective. Some opt for 90 days which if chosen to put the historically high use month in the middle of testing. Contact Advanced Electric Solutions, Corp. to assist you in your electrical monitoring and power management.
