The following table provides a brief overview of important considerations with some of the most effective technologies. As for lighting, facilities for the test are a good idea, then work with manufacturers and distributors.
Make the most of HVAC
As a building, installation and performance drastically complete HVAC controls have improved, it is important to understand and properly use these controls. The starting point is with a clear vision of whatreally transpiring in your building, 24 hours a day, seven days a week.
What has happened with every device? On vacation? Weekend? As the seasons change, you go to change your business? It 'important to understand where and how energy is used to identify where waste occurs and where improvements can be implemented. Then it is essential to ask: "What exactly do I do these checks"
Energy management systems (EMS) are designed to operateindividual devices more efficient and allow the integration of devices that improve system performance. In a typical EMS, sensors to monitor parameters such as air and water temperature, pressure, humidity, flow and energy consumption. Of these credits electrical and mechanical equipment run times and set points are controlled.
Seven days of programming offered by the hour and day after day explaining the control of HVAC and lighting systems and canHolidays and seasonal changes. As the name suggests, allows you to night setback temperature for less cooling in summer and heating in winter, less during off hours.
Optimum start / stop can look forward to the entire system for several hours and, according to current conditions, decisions about how to proceed, this system allows the ramp slowly, avoiding unnecessary or morning periods of peak demand.
Peak electricity demand can be controlled by sequencing of fans and pumpsStart one after the other, rather than all at once, off pieces of HVAC systems for short periods (up to 30 minutes), should only minimally affect the temperature. Economizer to reduce cooling costs by using cold outside air. Restoring the air temperature can help prevent excessive heat and chiller to load.
An EMS can have a wealth of information about the performance of the building, but someone to understand what they want and then give to the EMSDirections. Calibration controls, checks and balances are the key to any well-maintained HVAC system, but are particularly important to optimize control.
Variable speed motors and high efficiency
Variable speed drives (VSD) are almost always recommended as a reliable and cost effective upgrade.
VSDs are profitable, where the unit is oversized and often operate at partial load. Save up to 70 percent can be achieved by the installation of VSD fan motorsOperating at partial load. Can be used with a compressor or pump motors and are usually variable air volume (VAV) is used. They are also inexpensive water-side applications. Tilted back and VSD airfoiled fans are the best candidates.
Air handling configurations with variable guide vanes inlet or outlet dampers are wasting energy control operating at partial load. Flow valve for smaller pumps to reduce stress, it is also inefficient. The efficiency ofEngine begins to decrease dramatically when they run with less than 75 percent of full load, you can have an output more than double what the load needs. VSD to operate electronically and continuously adjust the motor speed to match the load.
The power stroke VSD is proportional to the cube of speed (or flow), which is why this technology is so efficient. If the speed is reduced by only 10 percent, would bring a 27 percent reduction in energy consumption. A pilot study found EPA VSDRetrofit VSD who made an annual average energy saving of 52 percent, an average demand savings of 27 percent and a 2.5-year simple payback.
Perform harmonic, power factor, electrical load and torsional analysis before choosing a VSD. Although the power factor and harmonic problems are not common in applications should VSD VSD usually with integrated mains filter (or three-phase AC Reactor) and internal compensation capacitors (or a single capacitor can be equippedVSD "switch line). In general, this device is not standard and are specified.
A better design and materials to improve the performance of energy efficiency of motors that use energy from 3 to 8 percent less than conventional engines, devices with efficiencies of 95 percent available.
For maximum savings, the engine must be correctly matched with its load, causing the battery life with maximum efficiency. The engines work best when running at 75 to 100 percent of their fullRated load; engines routinely operating less than 60 percent of rated capacity are prime candidates for retrofitting. For motors, the load can vary, the VSD should be considered.
Smaller, more efficient engines are part of a ploy undermined the system, downsizing a 75 horsepower engine with 40 hp standard energy-efficient model will result in energy savings of 15 percent.
Some energy-efficient motors have less "slip" as the standard engine efficiency, which leads to high energy efficiencySlightly higher engine speed, consider a greater role for the higher speed to compensate and to maximize energy savings. The installation of a new pulley or adapt the existing one can be an alternative when the cost of a VSD VSD or prohibitions of the load is reduced.
The improved performance of the system fan
A common way to improve the efficiency of air distribution, constant air volume (CAV), conversion to VAV systems. An authority on energy issues,E-source, reported that "typical (VAV) air-flow requirements, only about 60 percent will go the entire CAV".
VAVs response requirements by varying the volume of air through a combination of shock and pressure switches, instead of loading by varying the temperature. After the low pressure air fan power, and the volume of air-conditioning, thus increasing energy efficiency. Of course, it is essential to maintaining indoor air quality (IAQ), ventilation systems, if the changeSystems.
VAV systems to maximize the savings should be the VSD, the propeller blades, speakers, mixers and VAV boxes to operate properly, careful zoning is also required to obtain the optimization of VAV.
It is recommended to consider the source-VAV retrofit the following methods:
• complete relief measures and calculate the maximum and minimum air flow,
• Measure the fans use existing channels to investigate possible system improvements,
• Phase array fans that are parallel,
• Commissioning of the system completely
• Optimization of the static control pressure setpoint reset and implement, and
• Remove all exhaust fans.
Motors with low power consumption and size are also recommended appropriate strategies to control accurately. The installation of a self-contained, thermally-driven device for each speaker can add more control of VAV systems, the control of individual areas, rather thanall areas, and the need for VAV boxes. This device also offers style VAV systems skills CAV.
VAV retrofit costs and reimbursement can vary widely. The installation problems associated with fan control reduces air, the position of pressure sensors and their reliability, as well as poor design can reduce the performance of a VAV retrofit. Since VAV boxes are relatively expensive and is required for each zone, is not generally convenient forPartition the space into different zones. Gain depending on occupancy, internal loads and solar energy - - designation of the area carefully maximizes efficiency, increases comfort and reduces the heat again.
If not eliminates warm-up, these steps to minimize it: Ensure thermostat setting, increasing the air temperature during the hot season and warm throughout the year and monitoring can only use warm during the winter months. Where is first heated again to control the humidity, aAbsorption or a heat pipe may be considered.
Downsizing existing VAV ventilation systems is a relatively inexpensive way to save energy when the loads have been reduced or if the air distribution was oversized to begin with. Below are resources for fans or air flow to reduce the requirements:
• Reduction of the nominal value of static pressure to the actual temperature and airflow requirements.
• Right-sized engines and upgrading to energy-efficient models, installing larger wheels.
• Replace the existing fan pulley with a larger one, which will reduce the requirements of the fan, reducing their speed.
• Make sure the fan speed to match the load. Reducing fan speed by 20 percent reduces energy consumption by about 50 percent.
There are several ways to determine if the VAV fan systems are oversized. If an engine power of the measured current is 25 percent less than their nominal rating plate is oversized. If a fan intake and exhaust valvesDampers are closed more than 20 percent, is oversized. If the reading of static pressure is less than the nominal value of static pressure inlets or when shutters are open and windows open VAV 100 percent, as in a hot summer day, the system is oversized. Again, you should consider the IAQ requirements for the design of ventilation systems.
Chillers and thermal storage
No one wants a very good cooler, just because the withdrawal to replace CFCs. But as soon as the load reduces the efficiency for updatescompleted, it can actually be profitable to replace a radiator large. This is especially true in the face of rising prices and tightening supplies of CFC refrigerants.
Large equipment 10 years or older are good candidates for replacement. A highly efficient intercooler lowers energy costs for the entire duration, the initial costs are reduced because the radiator replacement is smaller than the old one. Depending on the performance of the old system and the load, a radiator with high efficiency of energy consumptionto.30 can be.15 kW / ton less, reducing energy consumption by up to 85 percent when combined with scaling.
It can accommodate an alternative to replace cooling equipment for the retrofitting of a new refrigerant, and to adapt to the loads. This may include the replacement of the panel, spare wheel and compressor can be replaced, depending on the specific chiller.
The retrofitting can bring poetry and the replacement of the seal and motor rewinding. Depending on the coolant and the way in whichMeasurement can be performed either loses efficiency and cooling capacity. To determine whether replacement or upgrading is a better choice, should cover educational costs and life cycle.
Retubing the condenser and the evaporator ensures considerable energy savings, but if it makes sense, given the high cost, depends on the conditions of the chiller. Water cooled condensers are usually more efficient than air-cooled. As water flows through a condenser in open loop, is likely toPollution. Calcification inhibits the efficiency of heat transfer, maintenance is therefore necessary to clean the surfaces.
Absorption chillers are an alternative to models of centrifuges. Absorption chillers cost up to $ 150 per tonne more than the machines as a vapor compression cooling unit spin, but in areas with high rates demand for electricity or gas or vapor that is available, cost effective, depending on the structures local utility rate. With a combination of the two types of chillersreduce the cost of electricity demand.
Thermal energy storage (TES) chiller equipment used to produce conventional treated water or ice (or occasionally another phase change material) in non-peak hours. The water is withdrawn from storage during the day or during peak hours and circulated through the cooling system.
TES systems can be integrated into new and existing systems and can provide partial or total displacement of the cargo load. TES helps to reduce operating and maintenance costs;In some cases, a small cooler can be specified. Some systems provide air supply and bottom water temperature, so that the requirements of the flow of air and water can be adjusted.
Water-side improvements
Fill, the size and efficient cooling fan tower configurations. Cell filling (also known as packaging films) increases the efficiency compared to other types of coverage. Can oversized tower closest approximation at room temperature wet bulb temperature allow to increase efficiency. Generous size of the tower andan increase in the proportion of the load chiller can be economically sustainable, because a cooling tower of the initial costs and energy consumption per ton less than a car cold.
At partial load, the application of a VSD for the fan (or pump) to improve the efficiency of the tower. Systems with variable speed drives and several fans are more efficient if all the tower-cells are operating at reduced speed, one or two cells at top speed towards.
Since the cooling towers contain large areas of the heat exchanger, pollution - or the scaleMucus accumulation - can be a problem. The efficiency of the systems used improperly can be improved with an effective water treatment. Towers high-efficiency, induced draft types are more popular and more efficient than forced draft towers. The performance can be improved with an increase of surface cooling.
In the traditional system of pumping, the flow is generally constant volume, a reduced flow of gas at partial load, the efficiency of inhibition.
Install VSD on the secondaryTo pump in variable flow systems, pumps and motors to rightsizing to meet the load, and development of systems for single-loop configurations loop primary / secondary, performance and reliability of pumping systems. Chilled water pumps in modernization, it is important to meet the minimum and maximum flow rates through the chiller.
Other cooling options
Desiccant dehumidification reduce materials that are integrated into the HVAC systems for cooling loads and canChiller efficiency, improving air quality in indoor spaces and comfort. Previously only in niche industrial applications, desiccant cooling extends through the commercial markets.
Useful for regenerating desiccant when the cost is lower than the cost to below the dew point and can dehumidify HVAC energy load and peak of over 50 percent in some cases reduced.
Evaporative coolers provide the most efficient and economical cooling, with up to 75Percent less energy compared to vapor compression systems. Although the cost is higher, reaching reimbursement for evaporative coolers from six months to five years. Although evaporative coolers are particularly common in the arid west and southwest, are most U.S. climates. E-source states which can eliminate, in combination with evaporative cooling, desiccant cooling refrigerated air conditioning in different climates.
Hybrid systems that integrate with evaporative coolingConventional HVAC technologies offer additional possibilities. To improve performance, superior low air speed, better packaging materials, with fan, pump and motor efficiency, including VSD, better belt or direct drive, better housing, better grip and control. Proper maintenance is the key to energy efficiency.
Conditioners are usually in buildings or parts thereof, which is where the cooling load is less than 75 tons. These units can operate at partial loadsignificantly reduce the efficiency. They are generally not as efficient as cooling systems, but can be updated and replaced when Rightsized. Existing systems can increase the efficiency of compressors, condensers and evaporators and large VSD, although the life expectancy of 10-12 years may mean for these technologies is that the updates are convenient for improvement.
Heat pumps are the most energy-efficient heating and cooling technology available today. Low operating costs, increasedReliability and long life to improve their profitability. They work best in temperate climates and sizing is critical.
Multi-unit configurations can serve larger loads and provide zoning, large, central modernized units with capacities up to 1,000 horsepower or 750 kilowatts is gaining popularity. Air-air heat pumps are the most common type because of the low-cost up-front, the mass supply of heat pumps are more efficient, but tend to have higher initialCosts.
Boiler upgrades
Check with fuel and air flow on a range of load conditions and a greater heat exchange surface - - especially in colder climates, the improved performance of the boiler can make a significant contribution to energy saving. Smaller units are organized into modular systems, increasing efficiency up to 85 percent, while the replacement of smaller units with the open loop condensing technology to fuel the combustion efficiency up to 95 percent.
Boiler conversions, in combination withimproved maintenance procedures can increase efficiency - up to 90 percent. New burner, baffle inserts, combustion control, controls heat recovery economizers changes, heat recovery and condensate drain to provide opportunities for greater efficiency. A little 'boiler "Summer" might be a good option if a boiler all year round, however, be kept at reduced capacity in warmer conditions. The boiler in the summer is much smaller in size for small loads, the largest boiler offdown.
HVAC upgrades can provide enormous economic benefits to improve occupant comfort and system reliability and reduce operating costs. But in order to maximize benefits and minimize investment, measures to reduce the load, such as lighting upgrades, HVAC system upgrades should precede.
