HVAC - Reading Journal
Rosa and Christensen present a new method for district heating that achieves low energy based on its relatively low temperature requirements. The development of this innovative new district heating method has led the authors to compare its cost-effectiveness with more traditional methods, and this research is carried out among low energy requirement dwellings in Denmark. During the course of this study, the authors found that human behaviour accounted for a large portion of the variability that was demonstrated in energy needs in the area. This increase was measured against standard values for energy demand in energy efficient buildings. The authors claim that this relatively large impact of human behaviour should be incorporated in future simulations seeking to measure potential demand for energy. The authors continue to emphasize the positive aspects of their proposed new low energy direct heating solution, asserting that its consistency helps to protect energy supply both cost-effectively and in a manner that is friendly or innocuous to the environment where linear heat density stays below a particular level (0.20 MWh/(m year)).
Efficient HVAC Design
Rosa and Christensen begin by emphasizing the potential for district heating, or DH, to account for up to sixty percent of demand for heating in Denmark. As well, direct heating allows the energy system as a whole to increase its proportion of energy from renewable sources. The upshot, the authors claim, is that heating systems can potentially achieve drastic savings and achieve greater overall efficiency. The authors note that the district heating solution they propose can sate the demand for energy both in cold climate countries, and also in others as well. The DH method espoused by the authors can, however, be inefficient in cases where the large initial startup capital investment requirements outweigh potential cost savings from operational efficiency gains. Traditional heating networks operate inefficiently, in contrast, through ‘over-dimensioned design’ and overly high temperatures. As such, the district-heating model presented by the authors seeks to provide comfortable Domestic Hot Water (DHW) and Space Heating (SH), improve efficiency by minimizing exergy, which would be achieved by bringing the temperature of energy demanded to that supplied into alignment, and also to minimize the loss of heat produced by the system.
Kanagaraj and Mahalingam find that there is an Integrated Design Process for achieving an energy efficient design for a building in the design phase. Yet this Integrated Design Process is difficult to apply to actual buildings due to its preliminary, abstract, and theoretical nature. Thus, the authors propose a number of methods to enable a more practical approach to achieving an energy efficient design for a building in the design phase. The authors construct a framework that allows designers to more practically integrate concerns for energy efficient design at each stage of the design process. This new process is designed to enable designers to choose between various energy efficient options that are available to them, on a contextual basis according to the kind of system or structure they are considering and the specific constraints they face. As well, the process is supposed to take advantage of the newest technology in design to enable the use of newfangled analysis tools designed to aid a more holistic and integrated design approach. The authors term their new process an ‘Integrated Energy-Efficient Building Design Process’. The authors also introduce to the reader and explore the implications of using Analytical Hierarchy Process to balance between design priorities in order to settle on suitable compromises during the design process.
The authors then go on to detail the real world application of their proposed framework in the construction design of a building in India. The authors find, of course, that their methods resulted in substantial improvements to energy consumption, leading to significant energy savings for the design. The authors simulated the effectiveness of their method by comparing the office building design it produced with design produced without their proprietary process. The authors made the study more effective by offering the design projects to real life architects who then produced designs using either the authors’ IEBDP method, or a different method.
From an evaluation done in the aftermath of these real world simulations, the authors found that their IEBDP method helped designers to produce better designs, ones that were more energy efficient. The purpose of the paper was to prove that integrated design allows designers to more effectively coordinate design processes and priorities across various concerns that, under more traditional design practices lacking such state of the art tools and processes, would not be so integrated or harmonious. The lesson for this literature review vis a vis the IEBDP framework is that it is beneficial to energy conscious design to focus on how different design parts and priorities work together to produce a final product which, in the end, together add up to a level of energy requirements. In other words, a large energy savings in one area of the design can be lost in other parts of the design. The integrated approach, by contrast, allow designer to find energy savings by focusing on how portions of a design work together to determine a building’s total energy requirement.
Schulze and Eicker focus on ventilation problem solving for energy efficient buildings. This new ventilation proposal by the authors focuses on what they call natural ventilation. Natural ventilation, they say, can result in less energy usage on cooling systems and efforts and smaller use of electricity devoted to the usage of fans. The authors argue that natural ventilation has a high chance to improve energy efficiency the globe over, because such practices are rare and not widely utilised, although their implementation represents much higher global efficiency in future. One reason that natural ventilation has not achieved widespread adoption on a global scale is partly due to the fact that not enough is known about the thermal comfort it is capable of providing in lieu of more traditional air conditioning methods of thermal relief. Thus, the paper presented by the authors engages in a study of just such variables and differences. Studies of natural ventilation airflow networks in tandem with building simulations were used by the authors to find the effectiveness and efficiency of natural ventilation solutions. The study found that natural ventilation excels at both cooling and energy efficiency; however, one of its chief drawbacks is, ironically, that it cools a little too well in the summer months and especially during the colder seasons in the context of temperate climes.
Schulze and Eicker conclude that natural ventilation indeed has a number of benefits as compared to more traditional air conditioning and ventilation techniques. These benefits include less energy usage required by buildings with natural ventilation, due to the fact that natural ventilation does not require much mechanical equipment to work properly as does central air conditioning. Further, the authors claim that natural ventilation leads to higher quality thermal comfort in comparison to more popular methods of ventilation as well. The key is to establish what the authors call steady state airflow, and their paper was pivotal for natural ventilation because it was able to simulate the functions and attributes of such airflow in order to examine its natural ventilation traits more rigorously. The findings of the authors relate to my work because they suggest that natural ventilation is a viable alternative, and, moreover, a more energy efficient one. All buildings designs should strive to incorporate natural ventilation.
For their part, Gieseler and Heidt study the economics and financial impact of a particular building designed to be energy efficient. In so doing, the authors study the varying economic efficiency levels of thermal insulation of different intensities. The authors achieve these estimates through a rigorous examination of a single-family dwelling located in Germany that utilises the latest in efficient construction materials. What is more, the authors give a definition for what constitutes cost efficiency for buildings designed with energy efficiency in mind. This definition both allows the authors to identify the cost efficiencies of existing designs and also to establish criteria for future energy efficient designs as well.
The authors find through their study that homes located in temperate climates, like Germany and other parts of East Europe, the level of cost efficiency of varying degrees of thermal intensity can be calculated according to the formula they give, which takes into account local energy prices and prevailing interest rates. The authors also find that high levels of thermal insulation result in more comfortable internal temperatures inside the home they studied. Yet the cost savings for the particular German dwelling the authors studied seems to be nonexistent, as even the authors admit that higher insulation and better comfort come at a cost that is ‘rather high’.
Persily and Emmerich study how the air quality in sustainable and efficient buildings varies, and according to which principles it does so. The authors claim that new concerns about sustainability and so-called net-zero energy usage make it the right time to examine exactly how designers can balance the twin priorities of air quality and energy efficiency. The received notion is, however, that indoor air quality is not compatible with a goal of energy efficiency, as, traditionally, in order to achieve higher air quality designers had to sacrifice some energy efficiency and vice versa. This study dovetails somewhat with the above, which established the feasibility and energy efficiency possibilities of natural ventilation. Indeed, what the authors, for their part, term ‘outdoor air ventilation’ can result in, they find, a higher level of energy efficiency and, at the same time, a higher level of indoor air quality. Some new techniques to balance these two priorities in the context of natural ventilation are also discussed, such as increased envelope airtightness, heat recovery ventilation, demand controlled ventilation, and better maintenance of the ventilation system.
HVAC and Energy - Analytical Report
Examine the role of improved energy efficiency in buildings to contribute to sustainable development, and investigate the implications for prospective construction professionals.
This paper was undertaken with the purpose of surveying recent developments in HVAC and construction technology affecting the area of energy efficiency. In order to meet this purpose, a reading journal is included that presents the reader’s impressions on the works provided. The report includes journal article key points, an attempt to relate covered material and studies to the topic of energy efficiency, and a survey of points in the journal article that are useful vis a vis the report topic. This analytical report of will also focus on how the improved energy efficiency represented by these studies contribute to more sustainable development. Moreover, stated developments in efficiency will be analyzed with respect to their implications for construction professionals.
This analytical report examines a number of ways that builders are approaching the problem of a more sustainable and energy efficient catalog of construction techniques. In their turn, we will examine the efficiency of natural ventilation, which utilises an open-air design to provide comfort during the hotter months while saving on energy usage, district heating methods which attempt to solve the problem of many local heating elements which, collectively, represent a profound cost and energy inefficiency; a thermal insulation technique using new materials that professes to save on energy usage and increase cost efficiency as well. The usefulness of these techniques as well for my current purposes in studies will be examined and commented upon.
The system described by Rosa & Christensen, however, requires heavy capital investment that is only recovered over time through returns from efficiency gains, and after consideration of negative externalities of more traditional systems that are negated through the system’s more environmentally friendly operation. Further, cost savings are significant, but only when taking a holistic view which considers indirect costs and benefits from the savings in environmental costs, the taking advantage of new opportunities for energy savings, and the lesser incidence of negative health impacts and potential positive health impacts of the proposed DH system are taken into account as well. Much of these savings require effort to ascertain, as they are non-market externalities. The authors note in their conclusion that the best configurations for the low-energy DH concept they propose require low-temperature operation instead of low-flow configurations.
Figure 1: Network layout for terraced houses in Dalla Rosa & Christensen demonstrating heat load in Denmark
All of these papers help to develop the social responsibility of designers and the corporations that employ them. On this topic, Petrovic-Lazarevic speaks to corporate social responsibility in the Australian building industry. The author claims that achieving corporate social responsibility for the Australian building industry requires that construction companies in the country fulfill their moral obligations to all stakeholders in their activities. This includes achieving sustainability, a theme that has been a big focus in this particular paper. Indeed, the potential cost savings represented by all these energy saving techniques presented here represent a profound sea change in attitudes and construction design engineering know-how, and, if implemented by corporations such as those in the construction industry in Australia, could affect a massive change in total welfare and human comfort. In addition to the inherent value of pursuing sustainability and efficiency goals, achieving such goals will also add to the ever-important public reputations of such construction companies based in Australia. Reputation is an enormously valuable thing in the context of a corporation, whose public likeness is often invested, fairly or unfairly, in the limited scope of public information made available about the company. In this way, the importance of marketing and outreach efforts to publicize the benefits of sustainable building can be nearly as important as efforts to achieve sustainable construction itself, as a positive public perception about the basic activities of a corporation can indeed affect its ability to carry on doing those very things.
While reputation is an important component of convincing public and private investors alike in providing the extra capital sometimes required for more efficient designs, the Australian Sustainable Built Environment Council emphasizes, as well, the importance of both research generation and knowledge dissemination in enhancing the efficiency of the built environment (Australian Sustainable Bulit Environment Council). The implications of this emphasis for prospective construction professionals is that they must support such outreach and information efforts in order to fill their role of sustainable building advocates, and to get more work building sustainable buildings.
In addition to research and knowledge generation, the Australian Sustainable Built Environment Council claims that builders must engage in consultation, cooperation, and collaboration with stakeholders in their projects. This implies that prospective construction professionals must become more social than they have perhaps been in the past, making it a point to engage in outreach efforts with members of the communities their designs will eventually affect. What is more, partnerships between builders and governments are also important, as government is now an interested stakeholder in sustainable development, as has been demonstrated by the raft of sustainable building incentives and laws passed in many countries over the past decade. The advances in energy efficiency enumerated in part 1, above, represent real opportunities for sustainable development that can utilise such government incentives.
For my purposes, Persily and Emmerich shows that, with new technologies, science, and techniques, designers can now attempt to find a better balance between air quality and energy efficiency, and do not necessarily have to sacrifice one for the other any longer. Advances such as these represent prime examples of efficiency improvements that more easily their sometimes-lofty initial capital investments, as they promise an improved built environment in addition to higher energy efficiency. Such improvements can be installed in high value buildings, such as preexisting and new luxury dwellings, with the promise of better living in addition to higher energy efficiency. Thus, higher efficiency designs can find the way into more new buildings by bundling comfort features with higher efficiency. This could represent a potential boom for construction professionals, who can fetch higher fees while also implementing more environmentally conscious and sustainable designs.
To conclude, Geisler et al. emphasizes the importance of using the formula presented in the study to find the optimal level of thermal insulation, balancing the competing concerns for comfort and efficiency, which ultimately results in cost savings or loss. Such techniques can be combined by construction professionals with advances, such as the one described in Persily and Emmerich, to result in a higher global energy efficiency level. The application of formulas provided by Geisler et al. can locate areas of the globe where energy efficient designs will have the highest impact in terms of cost savings, and the designs described in Persily and Emmerich can then be implemented in locales thus identified. Such combinations of recent statistical techniques and technological innovations for energy efficiency imply that prospective construction professionals can concentrate their efforts on specific locales for maximum impact on welfare.
DALLA ROSA, A. & CHRISTENSEN, J. E. Low-energy district heating in energy-efficient building areas. Energy, 36, 6890-6899.
GIESELER, U. D. J., HEIDT, F. D. & BIER, W. Evaluation of the cost efficiency of an energy efficient building. Chicgao Renewable Energy, 29, 369-376.
KANAGARAJ, G. & MAHALINGAM, A. Designing energy efficient commercial buildings—A systems framework. Energy and Buildings, 43, 2329-2343.
PERSILY, A. K. & EMMERICH, S. J. Indoor air quality in sustainable, energy efficient buildings. HVAC&R Research, 18, 4-20.
PETROVIC-LAZAREVIC, S. Corporate Social Responsibility in the Australian Building and Construction Industry. Department of Management Working Paper Series.
SCHULZE, T. & EICKER, U. Controlled natural air ventilation for energy efficient buildings. Energy and Buildings, Chicago, 56, 221-232.
Council, Australian Sustainable Built Environment, Preparing for Change: A Climate Change Adaptation Framework for the Built Environment.
Council, American and Australian Sustainable Bulit Environment. The Second Plank - Building a Low Carbon Economy with Energy Efficient Buildings.