Search

Reducing household energy consumption is one of the most important strategies used to decrease fossil fuel consumption and greenhouse gases emissions, and to encourage renewable energy utilization. Most energy conservation strategies in the domestic sector are aimed at preferential loans, i.e., purchasing renewable electricity or to improve the efficiency of home appliances, such as air conditioning and lighting. However, despite the relative economic successes of these technologies, they have not had expected impacts in regard to energy consumption. In this work, the authors analyzed the consumption patterns of two equivalent households—one was adapted with improved thermal insulation and a 1.2 kW photovoltaic system to reduce consumption from the electrical grid. The results show that dwellings where no improvements were made registered lower electric energy consumption, due the fact that users were aware that no strategy had been implemented, and its consumption; hence, electricity payments depended solely on one’s attention over the electronic device operations. On the other hand, energy conservation strategies in households promotes confident and relaxed attitudes toward the use of energy, leading to lower energy billings, but a higher gross energy consumption.

In cities with dry arid climate, air conditioning (AC) equipment is necessary for thermal comfort in indoor spaces. The use of this equipment generates an increase in electricity consumption and an increment in CO₂ emissions to the environment, thus, one way to mitigate these negative effects is the Living Green Wall (LGW). The objective of this research is to assess the decrease in thermal gain, energy benefits, and estimate the greenhouse gas (GHG) emissions that are not emitted by the use of the LGW. Measurements of heat flux, solar radiation, and temperatures were made on a concrete wall and another with an LGW in a west-facing building in the city of Mexicali, Mexico. The results indicate that it is possible to reduce 49% of the heat flow through the wall, which reduces the thermal load 102,212 Btu/h to the indoor space, implying the additional work of 8.53 tons of AC. This excess equals 985.6 kWh of electrical energy and generates a total of 697 kg of CO₂ emissions during the warm season. It is concluded that shading with an LWG becomes a very influential element to mitigate the heat fluxes towards the indoor spaces.

This paper presents a hypothetical and comparative performance of a 5 ton air conditioner (AC) operating in two zones in different urban microclimates for 25 days. One site represents a type of homogeneous planned urbanism and the other is a traditional heterogeneous zone. Air temperature data was collected and then processed using a linear regression model included in the operating manual of the AC in order to obtain their energy consumption. Results indicate that for an area with 500 homes, a traditional urban complex requires 12,350 kWh of electrical energy more than a planned zone (1.89%). This extra energy amounts up to $1180 and adds 9191 kg of CO2 to the atmosphere. The increased energy consumption has implications that increase the cost and environmental aspects of two urban microclimates, so that urbanization without planning is less friendly to the environment. In this sense, this study highlights the effects of urban microclimates on domestic electricity consumption from air conditioning. In addition, for a city with an arid desert climate, the variation in electricity consumption is associated with changes in the urban mosaic. The results found represent scientific evidence that can be used as a reference to establish public policies that could be incorporated into the local construction regulations, oriented to reduce the energy consumption associated with the use of air conditioning equipment.

This article presents a proposal for the implementation of photovoltaic systems in homes located in Mexicali, Mexico. With exhibition of new insulation and different consumption characteristics. The photovoltaic low power system is proposed as a type of electrical supply that helps in reducing the environmental impact of generating energy by burning fossil fuels. A photovoltaic system installed in the city of Yuma, Arizona in the United States, which supplies the electrical needs to a building is selected as a reference for solar resource use. Energy use improvement and consumption costs are calculated, and the equivalent amounts of greenhouse gases, not generated since solar technologies were implemented are determined. Furthermore, comparisons of the solar potential between Yuma and Mexicali show that the Mexican city has a higher annual solar potential, so the applicability of this solar technology is too feasible in Mexicali.

A study was designed and implemented to simulate and validate experimentally the thermal performance and energy of two houses equipped for efficient use of energy in Mexicali, Baja California, Mexico. The objectives were the simulation and the assessment of energetic, economic, social and environmental impacts of the use of high efficiency air conditioning, high efficiency refrigerators, Solar Water Heater (SWH) and photovoltaic (PV) modules. The simulations carried out were validated by field measurements during years 2011 and 2012. For PV systems, we estimated generation of 1837 kWh/yr. and in the annual monitoring values were obtained 1855 kWh/yr. For SWH, the investment is recovered within a reasonable time (6 years) by saving conventional energy. Electricity consumption per unit area of building for winter and summer was 0.23 and 0.46 kWh/ft2, respectively. The field data of average power for the AC is consistent with the SEER 13 being of 1.0 kW, and for the refrigerator, average power was 128 W. For the 2-story house (1033 sq. ft.), simulation predicted an annual consumption of 4559 kWh and measured value was 4197, PV system contributed 55% of consumption. In regard to the estimated electric bill was for $233 USD, and the reported value was $207 USD. The PV cells contributed with 60%, and the electric utility invoice was $78 USD. In these prototype homes is significantly diminishing electricity consumption in contrast to habitual housing. When energy efficiency is achieved as a first goal, the contribution of renewable energy becomes significant. However, for the PV systems, there is much to do, as combining lower investment with funding polices, because, when energy use is reduced, by energy efficiency and saving programs, customers have a subsidized electricity rate. We strongly recommend focus the subsidy for the users and not to the electricity rates. The way to use energy and habits of user, impacts significantly saving actions and energy efficient and the development of renewable energy. It is not easy to compare houses with different family behaviors. We recommend carry out energy education programs, to induce the market for energy saving and renewable. The monitoring allowed a better assessment of current performance of photovoltaic modulus and inverters, and the effects of temperature; radiation changes due to shade and clouds; dust on surfaces, and of the quality and stability of the supply lines (voltage variations), over their behavior and efficiency. Finally, field experiences will help to develop non-invasive systems, using telemetry of data and control commands, which must be combined with the design of house facilities in such a way forward to smart systems.

This work describes the design, construction and test of a data acquisition system which performs the real-time monitoring and recording of temperatures in thermal envelope and water consumption in households. This system allows diagnosis and assessment of efficient use of water and a thermal report for electric efficiency purposes. The prototype was subjected to comparative tests with commercial instruments that were used during the project of collaboration with Universidad Autonoma of Baja California and Dennis engineering. The project was developed for energy-efficient housing prototypes for the middle market residential of Mexicali, localized at the state of Baja California in Mexico. At first case, a high gain or loss of heat causes significant increases of important loads as the refrigerator and air conditioning owing to their increment in operation times. Many efficiency energy projects make use of traditional systems for temperature monitoring, whose characteristics exceed the requirements for this type of application and they present economic disadvantages, which can be solved with virtual acquisition systems. Two virtual instruments in LabVIEW were developed which allow real-time acquisition, analysis and recording, with flexible viewing by the user of temperatures and volume of water consumed. Also automatically save data in excel files by specific times. This system can diminish the cost of a conventional temperature monitoring system with 8 acquisition channels approximately in a 50%, keeping precision and accuracy required for this type of applications. The dispositive has the flexibility for monitoring other variables for energy audit, and currently is being tested for climate and electric power parameters.Copyright © 2013 by ASME