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Summer Air-Conditioning Systems/Saving Natural Resources
Published in Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo, Energy Conservation Guidebook, 2020
Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo
As previously discussed in this book, one measure of efficiency is the EER, or the energy efficiency rating. The EER is determined by taking the Btu rating of an unit divided by the power it consumes (in watts). Higher EERs indicate higher efficiency. However, a new measure of efficiency has been adopted by the government and equipment manufacturers, the SEER, or seasonal energy efficiency ratio. This rating, mandated by the Department of Energy, is to be assigned to every unit sold in the U.S. Units produced after 1992 had to meet a minimum SEER rating of 10, and as of January 2006, units must meet a minimum rating of 13 SEER. Because units capable of higher efficiencies are typically more expensive to produce, they have higher cost. On the other hand, a higher SEER rating means higher energy cost savings. An air conditioning professional can calculate the proper SEER rating for any application. In addition to SEER rating, consumers may look for equipment that is energy star compliant. For example, energy star qualified central air conditioners are about 20% more efficient than standard efficiency products.
Heating, Ventilating, and Air Conditioning Systems
Published in Barney L. Capehart, Wayne C. Turner, William J. Kennedy, Guide to Energy Management, 2020
Barney L. Capehart, Wayne C. Turner, William J. Kennedy
Residential air conditioning units with capabities of five tons or less are rated with SEERS, and most air-cooled air conditioning units are rated in SEERs. Most water-cooled air conditioning units are rated in SEERs. Federal appliance efficiency standards and ASHRAE standards in 2006 set minimum SEERs for residential units as SEER 13. In 2015, the Federal SEER minimum went to 14 for air conditioning units sold in the southeastern and southwestern parts of the US. Smaller AC units can have SEERs of 30 today, with larger residential units of 4-5 tons having SEERs of 24. EER = Btu of heat removal of the AC system/Whof electric input to the AC system
Distributed Energy Systems
Published in Moncef Krarti, Energy Audit of Building Systems, 2020
where indices e and r indicate the values of the parameters, respectively, before and after retrofitting the cooling unit (i.e., adding the TES system), and SEER is the seasonal efficiency ratio of the cooling unit. When available, the average seasonal COP can be used instead of the SEER. Typically, the SEERchw for producing chilled water (to directly cool the space) is higher than SEERice for making ice (to charge the TES system).Q̇c is the rated capacity of the cooling system.X is the fraction of the on-peak cooling load (occurring during the hour when maximum electrical power demand is obtained) shifted to off-peak period.Nh,cTES is the number of equivalent on-peak cooling full-load cooling hours that have been shifted during off-peak periods by using the TES system.
Load-based testing methodology for fixed-speed and variable-speed unitary air conditioning equipment
Published in Science and Technology for the Built Environment, 2019
Andrew L. Hjortland, James E. Braun
Predominately, three figures of merit have been used to rate equipment performance: EER, SEER, and IEER (AHRI 2009, 2011). The EER, or energy efficiency ratio, is the ratio between the cooling capacity delivered by a system in kBtu/h to total power consumed by the system in kW at a specific operating condition. The seasonal energy efficiency ratio, SEER, is a binned based calculation relating the cooling capacity delivered and power consumed at different ambient conditions with an adjustment for part-load degradation that occurs due to cycling at low loads. The part-load degradation factor can be determined from a specific cycling test or a default value can be employed. The integrated energy efficiency ratio, IEER, is essentially a weighted average EER at different operating conditions.
Comparisons of load-based and AHRI 210/240 testing and rating for residential heat pumps
Published in Science and Technology for the Built Environment, 2023
Parveen Dhillon, W. Travis Horton, James E. Braun
In the U.S., the current testing and rating procedure for electric-driven residential air-conditioning and heat-pumping vapor compression direct-expansion (DX) systems is based on AHRI 210/240 (AHRI 2020) along with the method of test (MoT) outlined in ASHRAE Standards 37 and 116 (ASHRAE 2010, 2019). In the current testing procedure, a test unit's performance is measured in a pair of psychrometric test chambers serving as indoor and outdoor environments under required and optional test conditions with overriding native control settings. Equipment seasonal performance, SEER (Seasonal Energy Efficiency Ratio) for cooling and HSPF (Heating Seasonal Performance Factor) for heating, is estimated by propagating the measured performance through a temperature-bin method. Even though this current rating approach provides a standard metric of performance that is useful for comparing the relative performance of different systems, it might not be representative of the test unit’s actual field performance because it does not consider the embedded controls and their dynamic interaction with representative building loads. The effect of this was observed in different field studies by Larson et al. (2013), Munk, Halford, and Jackson (2013), and Proctor and Cohn (2006), where they observed a significant discrepancy in heat-pump field performance and their rated seasonal performance (SEER and HSPF). As an alternative, load-based testing methodologies have been investigated and developed for dynamic performance evaluation of heat pumps and air conditioners with their integrated controllers and other accessories by emulating building load and dynamic characteristics in a lab environment.
All-air system and radiant floor for heating and cooling in residential buildings: A simulation-based analysis
Published in Science and Technology for the Built Environment, 2020
Giulia Alessio, Giuseppe Emmi, Michele de Carli, Angelo Zarrella
The results for cooling are shown in Table 8. For the radiant floor with CMV the possibility in which the heat pump can work at two different supply temperatures is also shown (i.e. case R*). In the case of the radiant floor the thermal energy Qth includes the energy removed by the water flowing inside the pipes and the latent load removed by the dehumidifier. The all-air system removes 47% more thermal energy than the radiant system in Helsinki, 30% in Milan and 17% in Rome. The free cooling ensured by renewal air bypassing the heat recovery unit (Qfc) ensures a significant energy saving in all the locations. The electric energy consumption of the heat pump (which feeds also the dehumidifier), the dehumidifier and the auxiliaries are also presented: the total electric energy consumption of the two systems is almost the same in Helsinki, while in Milan and Rome the all-air system consumes respectively 14% and 29% less than the radiant floor system. The seasonal energy efficiency in cooling mode SEER, calculated as the ratio between the sensible and latent thermal energy removed by the refrigerated water and by the dehumidifier (Qth) and the total electrical energy consumption (Eel,tot,), is significantly lower for the radiant system with dehumidifier (2.9 in Helsinki, 2.5 in Milan, 2.3 in Rome) than for the all-air system (4.1 in Helsinki, 3.8 in Milan and Rome) because of the low performance of the dehumidifier. In fact, if the contribution of the dehumidifier is not considered, the seasonal energy efficiency value SEERrad is higher than the previous one (4.9 in Helsinki, 4.6 in Milan and Rome). Producing refrigerated water at a higher temperature when the isothermal dehumidifier is not working (case R*) has no significant impact on the total electric consumption, since the latent load in summer is dominant for most of the time.