http://www.ise.ufl.edu/capehart/papers/diversity.html
http://www.ise.ufl.edu/capehart/papers/ebaltemp.xls
这些东西是一个叫Barney L. Capehart教授的资料里面找到的，主要是用于计算用电费用。他的Use (or utilization) factor是用于计算用电量的，不是一般所说的利用系数，这里暂时称为使用系数，使用系数x年使用小时基数=年使用小时数。利用系数和这里Load factor 比较接近，这里暂时称为负载系数。Diversity factor 就是不同时系数。
Definitions:
1. Load factor - the ratio of the load that a piece of equipment actually draws when it is in operation to the load it could draw (which we call full load).
For example, an oversized motor - 20 hp - drives a constant 15 hp load whenever it is on. The motor load factor is then 15/20 = 75%.
2. Use (or utilization) factor - the ratio of the time that a piece of equipment is in use to the total time that it could be in use.
For example, the motor above may only be used for eight hours a day, 50 weeks a year. The hours of operation would then be 2000 hours, and the motor use factor for a base of 8760 hours per year would be 2000/8760 = 22.83%. With a base of 2000 hours per year, the motor use factor would be 100%. The bottom line is that the use factor is applied to get the correct number of hours that the motor is in use.
3. Diversity factor - the probability that a particular piece of equipment will come on at the time of the facility's peak load.
The diversity factor is the most complicated of these factors. For example, we might have ten air conditioning units that are 20 tons each at a facility. In Florida we typically assume that the average full load equivalent operating hours for the units are 2000 hours per year. However, since the units are each thermostatically controlled, we do not know exactly when each unit turns on. If the ten units are substantially bigger than the facility's actual peak A/C load, then fewer than all ten units will likely come on at once. Thus, even though each unit runs a total of 2000 hours a year, they do not all come on at the same time to affect the facility's peak load. The diversity factor gives us a correction factor to use, which results in a lower total kW load for the ten A/C units. If the energy balance we do for this facility comes out within reason, but the demand balance shows far too many kW for the peak load, then we can use the diversity factor to bring the kW into line with the facility's true peak load. The diversity factor does not affect the kWh; it only affects the kW.
Motor load factors in many facilities are more in the range of 40% - 50%, than in the range of 80% that had been a standard assumption for many years of doing audits. Rarely do you find a motor running at 100% load factor.
However, not all motors at a facility are running at the same load factors. Ventilating fans that come from a supplier as a packaged unit with a fan and a motor are most often assumed to be operating at near full load. You should probably use a load factor of 80% here, since the manufacturer of the ventilating fans should have reasonably matched these loads. Other motors may also be in this category - some engineering judgment and common sense are required to determine which other motors these are.
Motors with variable loads are going to have the lowest load factors in general. A dust collector fan motor will normally have quite a variable load, and would often be expected to have a low load factor. Other examples are saws, presses, milling machines, sanders and grinders, waste grinders, water pumps, hydraulic pumps, etc.
If a group of motors do not all operate together all of the time, then using a diversity factor is appropriate. This is the case with a number of separate air conditioning units (considering the motors for the compressors) that are individually thermostatically controlled. It could also be the case for a group of production motors if some of the motors are not in use all of the time. You should use a diversity factor in your motor calculations, since it is not often the case that a facility has all of the motors on at the same time.
Reconciling the energy balance: When you perform an energy balance, do not use the motor load factor as the first and only adjustment made to reconcile the estimated energy use (energy balance) with the energy bills. Making this adjustment too quickly results in failure to pick up other things that have been overlooked.
For example, if the energy use does not balance with the energy bills, the first step is to check to see that all of the equipment and uses have been accounted for.
Do the items on the energy balance spreadsheet match your recollection of the equipment you saw in the facility?
Does anything appear to be missing?
Are the utility bills for total energy use and peak kW recorded correctly?
The next step is to check the hours of use for lights and other equipment to see if it matches your knowledge of the facility's operation. Remember that each motor - as well as each other piece of equipment - does not necessarily operate the same number of hours each day or year. Finally, if some of the equipment does not come on at the same time as the facility peaks in kW use, then utilize the diversity factor to account for this.
Adjusting the motor load factors should probably be the last thing you do to reconcile the energy and demand balances. Now, if all other information and all other factors are correct to the best of your knowledge, then adjust the load factors. While motor load factors are not often in the range of 80-100%, you should be equally suspect of very low motor load factors. If you get motor load factors in the range of 20-30%, it is more likely that you have the hours of use wrong than that you have a facility which is using motors that are an average of four times too big for the job they are doing. Lumber mills and wood products facilities using lots of saws may have these low load factors. Most other places should have motors with a higher load factor.
Air handlers―use factor: Air handlers use motors and are subject to all of the comments made in the motor section. In addition, you may be able to get a better handle on the hours of use for the air handlers by knowing how the A/C system works. Ask if the air handlers run constantly when the facility is occupied. They might if the facility wants the ventilation, even though the compressors might not come on except to periodically provide some temperature reduction or moisture removal. If this is the case, then the use factor for these air handler motors should reflect an hours-of -use that matches the offices or other area that the air handlers supply. In addition, the hours-of-use must also consider the compressor run hours. Thus the total hours for the air handlers must be at least the same as the compressor hours, and may be higher if the A/C unit is left on during periods that the facility is not occupied, or if ventilation is provided.
If the air handlers only come on when the thermostat orders cooling, then the hours-of -use must be the same as the hours-of-use of the compressors.
It is important to get adequate information on the operation of the air conditioning system. To get complete data on the air handler motors for an air-conditioned facility, you will need all of the standard information - size, maker, single or three phase, etc - together with the operating basis for the air handlers discussed above.
You should also collect data on the drive belt system for air handlers. Record the number of belts, the lengths, and the types of belts. Ask about motor and drive lubrication and cleaning. Also check the A/C filters to see if they are reasonably clean.
Sometimes a visual inspection will show some real problems. Ask the maintenance person to open up one of the air handlers - or just look into it (SAFELY) if it is accessible - and see if the belt is tight, slack, or really loose. Do not stick your hand into an air handler that is off at the moment, and may come back on when the thermostat kicks in. Have the maintenance person turn the air handler motor off with the circuit breaker or control box. Do not put your finger on a moving drive belt.
Is the belt in good shape?
Is it frayed, cracked or coming apart?
Does it look like the pulleys for the motor and the fan are lined up?
Ask the electrician to measure the current that the air handler motor is drawing to see what its load factor is while driving the fan. It should be very near full load - but you never know. Maybe the original motor burned out and was replaced with a bigger one to "make sure it did not burn out again." Remember to take the full load current off the nameplate to find the load factor.
（1）
（2）
（3）
知，若把水看成不可压缩流体，则在工况A，B下功率之比为
（4）
。也就是说，式（1）成立的条件必须是泵的工作点A，B均在等效率曲线上。
（6）
，则C=Sa，因此泵的等效率曲线方程和管路特征曲线均为p=SaG2。当泵转速从n1变到n2时，泵的工作点从A点变到B点，B点仍在管路特征曲线上。由于泵的等效率曲线与管路特征曲线重合，则泵在A，B两点的效率ηa=ηb，这是闭式管路系统所具有的特点。
（7）
（8）
。但开式管路系统的阻力系统数 
，因为p0≠0，所以C a ≠S0。也就是说在p0≠0的开式管路系统中泵的等效率曲线与管路特征曲线不重合。把A，B′点的等效率曲线常数：
（9）
（10）
求得，而不等于 
。因为在开式管路系统中po≠0，A，B′点不在等效率曲线上，因此不能直接使用式（1）。
。根据上两式及式（5）、（6）、（7）、（9）及（4）联立即可求得相应的数值，本文利用作图法求解，以便于理解。
。
。泵在A，B′两点效率不同对节能的影响不可忽视，如果不计泵效率的变化，则
。与实际值的相对偏差为20%，而这一点往往容易被忽略。
。因此，对于开式、闭式系统当流量均从12.85 m3/h变到10.05 m3/h时，开式系统节能效果只有闭式系统的73%。
