Optimal Control Strategies for Switchable Roof Insulation Systems Applied to US Residential Buildings

Author(s):  
Ammar H. A. Dehwah ◽  
Moncef Krarti

Abstract Switchable building envelope systems, including passive and active systems, have recently seen an increase interest in the literature. Unlike static insulation, switchable insulation systems (SISs) have the ability to adjust the thermal properties of envelope elements. Advanced control strategies for SISs are evaluated in this analysis using genetic algorithm-based optimization techniques. In particular, this study investigates the potential heating and cooling energy savings for deploying optimal controls specific to SIS technologies when applied to residential roofs located in representative US climates. Moreover, energy use and peak demand savings obtained by optimal controls are compared with those obtained from the 2-step rule-based controls. Overall, the analysis results indicate that the maximum monthly additional savings obtained by optimal controls can reach up to 32% compared with 2-step rule sets when an annual analysis is conducted for a residential building located in Golden, CO.

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2917
Author(s):  
Mohammad Dabbagh ◽  
Moncef Krarti

This paper evaluates the potential energy use and peak demand savings associated with optimal controls of switchable transparent insulation systems (STIS) applied to smart windows for US residential buildings. The optimal controls are developed based on Genetic Algorithm (GA) to identify the automatic settings of the dynamic shades. First, switchable insulation systems and their operation mechanisms are briefly described when combined with smart windows. Then, the GA-based optimization approach is outlined to operate switchable insulation systems applied to windows for a prototypical US residential building. The optimized controls are implemented to reduce heating and cooling energy end-uses for a house located four US locations, during three representative days of swing, summer, and winter seasons. The performance of optimal controller is compared to that obtained using simplified rule-based control sets to operate the dynamic insulation systems. The analysis results indicate that optimized controls of STISs can save up to 81.8% in daily thermal loads compared to the simplified rule-set especially when dwellings are located in hot climates such as that of Phoenix, AZ. Moreover, optimally controlled STISs can reduce electrical peak demand by up to 49.8% compared to the simplified rule-set, indicating significant energy efficiency and demand response potentials of the SIS technology when applied to US residential buildings.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  

Since buildings are one of the major contributors to global warming, efforts should be intensified to make them more energy-efficient, particularly existing buildings. This research intends to analyze the energy savings from a suggested retrofitting program using energy simulation for typical existing residential buildings. For the assessment of the energy retrofitting program using computer simulation, the most commonly utilized residential building types were selected. The energy consumption of those selected residential buildings was assessed, and a baseline for evaluating energy retrofitting was established. Three levels of retrofitting programs were implemented. These levels were ordered by cost, with the first level being the least costly and the third level is the most expensive. The simulation models were created for two different types of buildings in three different climatic zones in Palestine. The findings suggest that water heating, space heating, space cooling, and electric lighting are the highest energy consumers in ordinary houses. Level one measures resulted in a 19–24 percent decrease in energy consumption due to reduced heating and cooling loads. The use of a combination of levels one and two resulted in a decrease of energy consumption for heating, cooling, and lighting by 50–57%. The use of the three levels resulted in a decrease of 71–80% in total energy usage for heating, cooling, lighting, water heating, and air conditioning.


Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski

A humidity-sensitive demand-controlled ventilation system is known for many years. It has been developed and commonly applied in regions with an oceanic climate. Some attempts were made to introduce this solution in Poland in a much severe continental climate. The article evaluates this system's performance and energy consumption applied in an 8-floor multi-unit residential building, virtual reference building described by the National Energy Conservation Agency NAPE, Poland. The simulations using the computer program CONTAM were performed for the whole hating season for Warsaw's climate. Besides passive stack ventilation that worked as a reference, two versions of humidity-sensitive demand-controlled ventilation were checked. The difference between them lies in applying the additional roof fans that convert the system to hybrid. The study confirmed that the application of demand-controlled ventilation in multi-unit residential buildings in a continental climate with warm summer (Dfb) leads to significant energy savings. However, the efforts to ensure acceptable indoor air quality require hybrid ventilation, which reduces the energy benefits. It is especially visible when primary energy use is analyzed.


2017 ◽  
Vol 7 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Kamalesh Panthi ◽  
Kanchan Das ◽  
Tarek Abdel-Salam

Purpose Vacation rental homes, in general, have different energy usage characteristics than traditional residential homes mainly because of the occupancy pattern that changes on a weekly basis. These homes, predominantly larger in size, offer a greater scope for energy savings also because of the wasteful habits of their seasonal occupants. The purpose of this paper is to investigate the causes of energy inefficiencies prevalent in these homes so that appropriate retrofit choices can be offered to homeowners. Design/methodology/approach This research presents a case study of a vacation rental home whose energy consumption was investigated in depth and energy inefficiencies identified through modeling using energy modeling software, eQUEST. Simulations were performed to identify viable retrofit scenarios. Findings While improvement in the building envelope such as providing shades/overhangs on the windows, reducing infiltration and increasing insulation of the exterior wall did not show promising results for savings on energy cost, other improvements such as use of highly efficient lamps, tank-less water heater system and occupancy sensors showed viable investment options with shorter payback periods. It was also found that energy use intensity of sampled houses was about half of the average of US residential buildings, which could primarily be attributed to the seasonal nature of occupancy of these houses. Originality/value There is a dearth of literature pertaining to energy efficiency-related retrofits of coastal vacation homes. This research fills that gap to some extent by addressing this issue with an ultimate aim of assisting homeowners in retrofit decision-making.


Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1912 ◽  
Author(s):  
Vasco Granadeiro ◽  
Margarida Almeida ◽  
Tiago Souto ◽  
Vítor Leal ◽  
João Machado ◽  
...  

This work addresses the effect of using thermochromic paints in residential buildings. Two different thermochromic paint types were considered: One that changes properties through a step transition at a certain temperature, and another that changes properties in a gradual/linear manner throughout a temperature range. The studied building was a two-floor villa, virtually simulated through a digital model with and without thermal insulation, and considering thermochromic paints applied both on external walls and on the roof. The performance assessment was done through the energy use for heating and cooling (in conditioned mode), as well as in terms of the indoor temperature (in free-floating mode). Three different cities/climates were considered: Porto, Madrid, and Abu Dhabi. Results showed that energy savings up to 50.6% could be reached if the building is operated in conditioned mode. Conversely, when operated in free-floating mode, optimally selected thermochromic paints enable reductions up to 11.0 °C, during summertime, and an increase up to 2.7 °C, during wintertime. These results point out the great benefits of using optimally selected thermochromic paints for obtaining thermal comfort, and also the need to further develop stable and cost-effective thermochromic pigments for outdoor applications, as well as to test physical models in a real environment.


Author(s):  
Niko Kalinic ◽  
Moncef Krarti

Calibrated energy simulations are often used to predict savings from energy conservation measures with little information about their associated prediction uncertainties. In this paper, the savings predicted by calibrated simulation models are compared to actual savings obtained through monitoring energy use before and after implementing selected energy conservation measures for three residential buildings. Both building envelope and HVAC system related energy conservation measures are considered in the study. Through case studies, this validity of using calibrated energy models for the estimation and verification of savings associated with energy conservation measures is thoroughly evaluated. Moreover, the paper provides useful guidelines for using calibrated models for measurement and verification energy savings from various weatherization programs specific to residential buildings.


2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 2951-2960 ◽  
Author(s):  
Ali Almarzouq ◽  
Ahmad Sakhrieh

The building envelope is the most affecting part in the energy interaction between the buildings and the surrounding. Proper design of the envelope components not only can save the required energy for the building but also can improve the thermal comfort of its occupants. In this research, energy modelling and simulation for a residential building in Amman, Jordan is performed to investigate the effects of glazing design and infiltration rate on energy consumption and thermal comfort. Different design alternatives have been investigated to find the best alternative design to reduce energy use and improve indoor environment. The results showed that replacing single glazing window with double glazing window argon-filled with low emissivity coating can save the consumed energy by 24.7% while degrade the thermal comfort by 1%. Reducing the infiltration rate by 50% can save 19.4% of the energy consumed and improves the thermal comfort by 10%.


Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2729
Author(s):  
Tiago Souto ◽  
Margarida Almeida ◽  
Vítor Leal ◽  
João Machado ◽  
Adélio Mendes

This work addresses the effect of the total solar reflectance (TSR) value of paints applied in residential buildings upon their thermal performance. A semi-detached residential building was modeled in the ESP-r software, and taken as the basis for parametric studies which assessed the effects of variations in (i) the TSR values; (ii) the thermal characteristics of the building envelope; (iii) the location/climate; and: (iv) the way how the indoor temperature is controlled. The parametric studies were used to find optimal TSR values for each combination of Location + Building envelope characteristics (mainly the existence of thermal insulation). It was concluded that paints having a carefully chosen TSR value lead to better indoor thermal temperatures if the buildings have no mechanical heating or cooling, or to energy savings of up to 32% if they do.


2019 ◽  
pp. 728-755
Author(s):  
M. Mustafa Erdoğdu ◽  
Coşkun Karaca ◽  
Ali Kurultay

The amount of energy consumption in the residential buildings has a very significant share with nearly 30 percent in the total amount of energy consumption. Therefore, residential sector is identified in this chapter as being one of the areas with a large potential for energy savings. Inefficient dwelling construction and design methods are widely used in Turkey and only about five percent of residential buildings are insulated. Concerning the importance and immediate need in Turkey for energy-efficient residential building retrofitting, this chapter identifies economic benefits of such retrofitting by particularly focusing on heat transfers by conductivity, where the rate can be determined by surface size, thermal resistance of the building materials and their thickness.


Author(s):  
S. Martínez Garriga ◽  
M. Dabbagh ◽  
M. Krarti

Abstract This paper evaluates the potential energy cost savings when high R-value static insulation layers as well as dynamic insulation materials (DIMs) are applied to residential housing located in Barcelona Spain. The analysis considers three dwelling prototypes to characterize the existing housing stock in Barcelona including detached attached and apartments. In addition three vintages for each housing prototype are defined: before 1979 when building envelope insulation took effect in Spain between 1980 and 2006 and after 2006 when the building envelope insulation code became more restrictive. Using a modified 3R2C network model to determine thermal loads the performance of both static and dynamic insulation systems is evaluated when applied to exterior wall for various housing prototypes in Barcelona. The dynamic insulation R-value is selected based on a 2-step control strategy. The analysis results indicate that DIMs with the largest R-value step (i.e. difference between the high and the low R-values) achieve the highest savings in source energy reaching up to 19% reduction in source heating and cooling energy for the entire housing stock of Barcelona. The annual energy savings achieved by DIMs are valued to be 181 M€/year for the entire existing housing stock in Barcelona. In addition electrical peak demand reduction associated with retrofitting exterior walls for the existing Barcelona housing stock can result in future avoidance of building new power plants and can provide additional 144 M€ and 162 M€ for respectively static and dynamic insulation systems. Considering the current energy mix applying dynamic wall insulation systems for Barcelona existing housing stock could reduce annual CO2 emissions by more than 300 000 tons or 6.80% of the total carbon dioxide currently emitted to heat and cool homes.


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