The implementation of energy efficient designed residential buildings and the direct effect on the thermal comfort of occupants in the New Zealand

In the wake of climate change disasters and campaigns all over the world, visionaries have ventured in the construction of energy-efficient buildings in New Zealand as a way of reducing the carbon footprint. In order to enjoy a good quality of life, an individual must first have proper and efficient housing. In New Zealand alone, residential buildings consume more than 80% of the total amount of energy produced within the country as well as generating the bulk of carbon emissions, thereby increasing their effect on climate change. Therefore, there has been a rising need for better building designs that are energy efficient and perform better than the already existing residential buildings. This research paper will shed more light on the various ways through which the occupants of residential buildings in New Zealand have been affected by the adoption of energy-efficient construction designs. Also, the thermal comfort levels of the occupants will be analyzed depending on their geographical location as well as their ability to control the environment indoors. This research paper is also going to analyze how these occupants are now able to predict their overall energy consumption levels based on thermal comfort models developed. The various risks that can arise if thermal comfort is exceeded are also discussed.

Keywords: energy, thermal comfort, energy-efficient, climate

Contents Abstract 2 What is the Impact of Thermal Comfort Models on the Ability of the Occupant to Predict Their Energy consumption? 5 Why Does Occupant Control Of Their Indoor Environment Is Important and Varies With their Geographical Location? 7 How Does The Façade of A Building Affect The Level Of Indoor Thermal Comfort Experienced By the Occupant of A Residential Building? 9 The Implementation of Energy Efficient Designed Residential Buildings Is Vital To The Thermal Comfort of its Occupants. But is it Sustainable? 11 What Are Some Of The Risks That The Occupants Of Residential Buildings In New Zealand Face As A Result of Extending Their Level of Thermal Comfort? 13 Conclusion 15 Recommendations 16 References 18

The occupants of residential buildings across the world have often wanted to exercise a certain level of control over the level of thermal comfort that they experience in their houses. It is therefore important for occupants of residential buildings to be able to efficiently predict how much energy they will consume in a given span of time. Over the years, various models have been developed to try and effectively predict the amount of energy that is being spent in the average household. Also, studies have been conducted to try and estimate the amount of energy spent in residential houses because residential buildings have been found to be one of the largest co0ntributors of greenhouse emissions of gas as a result of the huge energy being consumed by such buildings. There is, therefore, a desperate need to reduce the effects of residential energy consumption on the climate. Various engineering solutions coupled with energy-efficient structural designs are the best way of enhancing efficient use of energy in residential holdings.

Adaptive Thermal Comfort

(https://medwinpublishers.com/EOIJ/EOIJ16000119.pdf)

Research conducted in 2018 by several scientists revealed that thermal comfort models could be used to predict how much energy the occupant of a residential building is going to consume in a given period of time. The thermal comfort models make use of factors such as ventilation, heating, the air conditioning systems, as well as the geographical location of the residential holding. The research was conducted across several residential buildings with different physical attributes so that different results based on the factors being tested were obtained. The residential buildings that were selected for researched had all passed the safety test by the Building Code. The research analyzed the predicted mean vote (PMV) model as well as the adaptive thermal comfort models. The adaptive thermal comfort models turned out to be superior to the predicted mean vote (PMV) model because they did not have a lot of tedious calculations that the PMV model had. The adaptive comfort models highlighted the relationship between the outdoor temperature as well as the temperature desired for comfort.

Finding the most accurate thermal comfort model to use has always been the biggest challenge for those occupants living in residential buildings and want to predict how much they will use in the foreseeable future. Also, finding a model and mobile app that will effectively factor in all the variables involved in calculating and predicting energy use is very difficult. By making use of either the predicted mean vote (PMV) model or the adaptive thermal comfort models, occupants of residential buildings can effectively estimate their energy expenses, level of energy consumption as well as their thermal performance ("(PDF) The impact of the thermal comfort models on the prediction of building energy consumption," n.d.). By making use of efficient thermal comfort models when designing and building residential houses, occupants are assured of an easier way of estimating their energy usage and expenses. Also, efficient thermal comfort models increase the accuracy of the energy consumption predictions on New Zealand residents in residential buildings.

The need for energy-efficient buildings has continued to rise based on the findings that residential houses are one of the largest consumers of energy as well as emitters of greenhouse gases. Therefore, the burden falls o the designers to come up with energy-efficient designs based on the most beneficial thermal comfort models available for use. Whenever designers are coming up with the design for a residential building, their main focus should be on the needs and wants of the occupants of that building because they are the people who are going to benefit from the implementation of the energy-efficient design into the architectural design of the structure. Therefore, building design and the comfort levels of the occupant have to go hand in hand. However, most of the time, the occupants of residential buildings in New Zealand do not get to exercise a lot of control when it comes to their indoor environment because the designer or building contractor already hired a technical team to manager such activities for the occupants of the building. The figure below shows the operative temperate of the room with respect to the average speed of air as well as the level of control exercised by the occupant.

Operative Temperature versus Air Speed

(https://www.p2sinc.com/uploads/Energy-Efficiency-and-Thermal-Comfort.pdf)

The thermal comfort of the occupants of residential buildings can be attributed to either psychological factors or physiological factors. Such a factor is natural ventilation which not only affects residential settlements but all workplaces where the speed of the air as well as the levels of humidity in the air have to be monitored and effectively regulated in an effort to create a conducive working environment for employees at the office. There have been various studies conducted in New Zealand to try and show the relations that exist between the level of thermal comfort and satisfaction and the level of control they perceive to have over their indoor environment. Occupants of residential buildings often try to regulate their indoor environment through various ways such as opening windows, shifting to other parts of the building, making adjustments to thermostats, adjusting their modes of dressing and also making use of heating appliances or fans. Psychological results show that when occupants of residential buildings perceive that their level of control is high, they are more likely to be adaptive to the thermal environment created as a result of their control.

The geographical location of an occupant also plays an important role in determining their level of thermal comfort. For example, the occupants of residential buildings found in very hot and dry regions or those very cold (winter conditions), will tend to exert a higher level of control within their indoor environment so that they can maintain thermal comfort as well as be satisfied with the steps that they took to attain such levels of comfort. Below is a graph showing the level of control an occupant can exert on the speed of air in an effort to attain a steady and comfortable operative temperature within their indoor environment.

The façade of a building has a direct impact on the level of indoor thermal comfort that the occupants of the building can enjoy and attain satisfaction. The 21st century has brought with it very much technological advancement such as the construction of energy-efficient buildings as a way of tackling the energy crisis facing the world as well as the climate change problem. There is a lot of building construction as a result of the increase in world population. Therefore, construction contractors, as well as the building designers, are tasked with the duty of coming up with structures that consume less energy while at the same time increasing occupant thermal comfort. By coming up with an optimized façade for a building, the level of occupant thermal comfort can be significantly increased without having to increase the energy that is being consumed by the residential building. This is an important strategy because it helps in reducing the country’s (New Zealand) carbon footprint. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) states that thermal comfort is the state whereby the occupant of a building is comfortable with and satisfied by the thermal indoor environment ("Energy-efficient buildings are vital to sustainability," 2011).

According to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the main factors influenced by the façade of a building are temperature range, the speed of the wind as well as the level of humidity in the air. The figure below shows the acceptable operative temperature limits as per ASHRAE standards.

Temperature range as per ASHRAE standards (https://www.omicsonline.org/publication-images/architectural-engineering-thermal-comfort-6-218-g002.png)

The façade of a residential building is the one in contact with the external environment and is, therefore, most affected by factors in the external environment such as humidity, wind and sunshine. The effect of sunshine on a building has often been a bother in many residential buildings across New Zealand which has caused many occupants to move in and out of various buildings in search for their perfect house. However, with simple modifications to the façade of any building, the occupants of a building can effectively be able to attain thermal comfort. Extreme sunshine causes thermal discomfort because of the increased temperatures in the building. This can be mitigated by optimizing the materials that are used in making the façade of the residential building. Research studies conducted on mainland Australia have shown that buildings that have double bricked walls or those that have thermal insulation on their external surfaces have operative indoor temperatures that provide satisfaction to its occupants.

Also, by increasing the degree of shading, the occupants of the building will be able to enjoy thermal comfort because the scorching effect of direct sun rays falling on the building will be significantly reduced. Many buildings in New Zealand are picking up on the trend of introducing low-E covers for glass buildings as a way of reducing heat gain as a result of solar radiation on the building. Facades of buildings that allow for free movement of air also increase the level of thermal comfort of its occupants by a significant level. It is important to note that building contractors and designers should be cautious to select only those materials that will allow for maximum thermal comfort for the occupants of such buildings, especially if the building is a residential housing project.

In as much as it is necessary to maintain thermal comfort by making sure that constructions contractors and building designers come up with energy-efficient buildings, we must also ask ourselves whether this plan is sustainable in the long run. An article by Christian Kornevall featured in The Guardian in 2011, stated that the population of the world would have grown by approximately three billion. This rapid increase in population coupled with rapid technological improvement would mean that in the next two decades, the majority of the world's population will be living in major cities across the world. Today, most of the major as well as upcoming cities of the world are being faced with the problem of congestion and rising inflation rates. However, the majority of the buildings that are present today in New Zealand are energy inefficient and serve as a major contributor to the global climate crisis (Scott, 2018).

The United Nations Environment Programme (UNEP) Sustainable Social Housing Initiative (SUSHI) is one of the very many ways through which energy efficiency in the world can be achieved, especially in the construction sector. It should be noted that the construction industry accounts for approximately 8% of all employment in New Zealand and forms approximately 14% of the country’s Gross Domestic Product (GDP).

Efficiency of green buildings

(https://www.callisonrtkl.com/news/pablo-la-roche-shares-passive-strategy-with-bdc/)

It is for this reason that the implementation of energy-efficient residential buildings is being constructed at an increasing pace in an effort to meet the rising demand for housing as well as to reduce climate change effects. The question as to whether green buildings are sustainable has been effectively answered by research conducted by Asniza Hamimi Abdul Tharim and Muna Hanim Abdul Samad. In their research study, they stated that the sustainability of energy-efficient residential buildings incorporates numerous aspects such as environmental considerations, economic as well as social issues. The study revealed that the development of energy-efficient building designs and maintenance of indoor thermal comfort is sustainable both in the short term period as well as in the long term period. Despite the fact that energy-efficient buildings are more expensive to construct, their demand is steadily increasing as New Zealand citizens desire to live better and more quality lifestyles.

The increasing effects of climate change are being felt across the world, especially in New Zealand, and this has increased the need for effective indoor thermal control and thermal satisfaction. As a result, the concept of the implementation of energy-efficient designed residential buildings is vital to the thermal comfort of its occupants in New Zealand is sustainable ("review on sustainable design and indoor thermal comfort of a green building," 2016).

As stated earlier, occupants of residential buildings often have limited control over the energy efficiency levels of the buildings that they live in because most of the thermal comfort mechanisms were implemented by technical teams. However, thermal comfort can be termed to be more of a state of mind rather than a state of the body ("Thermal comfort," n.d.).

Thermal Comfort Extension

(https://www.p2sinc.com/uploads/Energy-Efficiency-and-Thermal-Comfort.pdf)

As a result, occupants of New Zealand’s residential buildings feel that they want more control over their indoor thermal environment and often make use of appliances such as fans and heaters as well as other methods such as adjusting their modes of clothing in an effort to regulate their indoor thermal environment. In an effort to increase the level of thermal comfort, sometimes an occupant exceeds the range of thermal comfort and faces certain risks. Many a time, the speed of air is not adjusted uniformly, which often leads to the formation of draught, which causes an increase in temperature and humidity, especially during the cold season. Most times during the cold season, occupants of commercial, residential buildings increase the temperature beyond the normal indoor setting as per the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) codes and end up overheating their houses. On the other hand, when the temperature is very high, the speed may not be adjusted uniformly, which ends up not meeting the required cooling effect that the occupant wanted.

A study was conducted in New Zealand to try and determine the number of times the owner of a house opens the window so as to facilitate free movement of air within the house (Site designed and developed by bka interactive ltd, Auckland, New Zealand (www.bka.co.nz), n.d.). The findings of the research study upheld the notion that thermal comfort is more of a psychological need than it is a physical need for the majority of the population. The findings revealed that most house owners just open at least one window to allow free air movement without giving any consideration to the temperature outside the house or the type of activity that is going on in the house at the time. However, it is often counterproductive to open a window when the temperature outside is equal to or is slightly higher than the indoor temperature because the action is more likely to lead to increased temperatures inside rather than provide the desired cooling effect. The good news is that if the occupant of the residence is well informed on their levels of thermal comfort, the occupant can effectively be able to reduce the risks associated with extending the limits of their thermal comfort range.

It is important to note that population increase has caused the demand for housing to significantly increase in New Zealand. The fact that residential buildings in New Zealand, as well as the rest of the world, have a direct impact on the global climate crisis presently being experienced means that there is a significant need for energy-efficient houses. Energy-efficient housing projects will ensure that the country's (New Zealand) carbon footprint is reduced because the amount of energy being consumed by residential buildings. It is also true to state that energy-efficient buildings have a direct effect on the indoor thermal environment that the occupants of residential buildings in New Zealand enjoy. Most of the times thermal comfort is mistaken for being a physical need for most occupants of such building, but rather it is usually a psychological need that the occupants of residential buildings want. Thermal comfort can be adjusted depending on the geographical location of the residential building as well as other aspects of the building such as its façade, its windows, the materials used to make the walls and even the coverings of the exterior of the building. In spite of the challenges and risks faced in an attempt to attain thermal comfort, energy-efficient housing projects still remain to be sustainable in both the short term period as well as the long term period.

Models that are being developed and used across the world have a significant impact on the ability of the occupant of a residential building to accurately predict the amount of energy that they consume over a specified duration of time. It is because of this reason that the occupants of commercial, residential houses in New Zealand should ensure that they use the most accurate and easy to use thermal comfort model to estimate the amount of energy that they use. Occupants of residential houses should also make sure that they exercise the right amount of control over their indoor thermal environment in an effort to avoid extending the thermal comfort limits and end up facing overheating or overcooling which does not offer them the satisfaction that they want. In order to make sure that the implementation of energy-efficient buildings across New Zealand is sustainable for an even longer period of time, further research should be conducted on green buildings and how they can improve thermal comfort for occupants of the green buildings. Green building technology should be invested in because of the steady increase in demand for proper housing amenities as well as population pressure. Building designers and construction contractors should make sure that the materials being used during construction will improve the level of thermal comfort being enjoyed by the occupants of the building. Aspects such as shading and ventilation and heating systems should be constructed in line with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) codes building.

A review on sustainable design and indoor thermal comfort of a green building. (2016, January 1). Retrieved from https://www.researchgate.net/publication/301634442_A_review_on_sustainable_design_and_indoor_thermal_comfort_of_a_green_building

Energy efficient buildings are vital to sustainability. (2011, April 1). Retrieved from https://www.theguardian.com/sustainable-business/energy-efficient-buildings1

Influence of the passive design of a building facade on the indoor thermal comfort of residential buildings. (n.d.). Retrieved from https://www.omicsonline.org/open-access/influence-of-the-passive-design-of-a-building-facade-on-the-indoor-thermal-comfort-of-residential-buildings-2168-9717-1000218-105447.html

(PDF) The impact of the thermal comfort models on the prediction of building energy consumption. (n.d.). Retrieved from https://www.researchgate.net/publication/328206062_The_Impact_of_the_Thermal_Comfort_Models_on_the_Prediction_of_Building_Energy_Consumption

Retrieved from https://www.p2sinc.com/uploads/Energy-Efficiency-and-Thermal-Comfort.pdf Comment by M'Archive: Why these four references have no title???

Retrieved from https://warwick.ac.uk/fac/sci/med/research/hscience/sssh/publications/publications14/thermal.pdf

Retrieved from https://www.omicsonline.org/publication-images/architectural-engineering-thermal-comfort-6-218-g002.png

Retrieved from https://medwinpublishers.com/EOIJ/EOIJ16000119.pdf

Pablo la Roche shares passive strategy with BD+C. (2018, May 15). Retrieved from https://www.callisonrtkl.com/news/pablo-la-roche-shares-passive-strategy-with-bdc/

Scott, C. (2018, February 14). Building a sustainable future: Why energy efficiency is everybody’s business. Retrieved from https://www.theguardian.com/sustainable-business/2014/nov/13/energy-efficiency-buildings-business

Site designed and developed by bka interactive ltd, Auckland, New Zealand (www.bka.co.nz). (n.d.). The future of building sustainably in New Zealand. Retrieved from https://www.altuswindows.co.nz/blog/2018/5/the-future-of-building-sustainably-in-new-zealand/

Thermal comfort. (n.d.). Retrieved from https://www.greeneducationfoundation.org/green-building-program-sub/learn-about-green-building/1239-thermal-comfort.html

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