The purpose of the Pilgrimage to the Night Sky is to encourage a self driven journey of rediscovering the beauty and simple pleasure of looking up and seeing a star-filled sky. The goal is to create two sites in the landscape that will act as the starting points to this pilgrimage by showcasing the stars in the night sky and will nurture the curiosity of those who have an interest in the heavens. A progression approach is meant to be experienced while on this journey, with the first stage of the pilgrimage taking place in Assiniboine Forest. The second stage of the pilgrimage takes place ten minutes south of the city at Glenlea Observatory which hosts an exponential increase of stars in the night sky. The practicum concludes with an assortment of resources people can use to continue their pilgrimage and search for their darkest night sky.

Low grade heat sources have a large amount of thermal energy content. Due to low temperature, the conventional power generation technologies result in lower efficiency and hence cannot be used. In order to efficiently generate power, alternate methods need to be used. In this study, a supercritical organic Rankine cycle was used for heat source temperatures varying from 125°C to 200°C. Organic refrigerants with zero ozone depletion potential and their mixtures were selected as working fluid for this study while the cooling water temperature was changed from 10-25°C. Operating pressure of the cycle has been optimized for each fluid at every heat source temperature to obtain the highest thermal efficiency. Energy and exergy efficiencies of the thermodynamic cycle have been obtained as a function of heat source temperature. Efficiency of a thermodynamic cycle depends significantly on the sink temperature. At areas where water cooling is not available and ambient air temperature is high, efficient power generation from low grade heat sources may be a challenge. Use of passive cooling systems coupled with the condenser was studied, so that lower sink temperatures could be obtained. Underground tunnels, buried at a depth of few meters, were used as earth-air-heat-exchanger (EAHE) through which hot ambient air was passed. It was observed that the air temperature could be lowered by 5-10°C in the EAHE. Vertical pipes were used to lower the temperature of water by 5°C by passing it underground. Nocturnal cooling of stored water has been studied that can be used to cool the working fluid in the thermodynamic cycle. It was observed that the water temperature can be lowered by 10-20°C during the night when it is allowed to cool. The amount of water lost was calculated and was found to be approximately 0.1% over 10 days. The different passive cooling systems were studied separately and their effects on the efficiency of the thermodynamic cycle were investigated. They were then combined into a novel condenser design that uses passive cooling technology to cool the working fluid that was selected in the first part of the study. It was observed that the efficiency of the cycle improved by 2-2.5% when passive cooling system was used.

abstract: As the demand for power increases in populated areas, so will the demand for water. Current power plant technology relies heavily on the Rankine cycle in coal, nuclear and solar thermal power systems which ultimately use condensers to cool the steam in the system. In dry climates, the amount of water to cool off the condenser can be extremely large. Current wet cooling technologies such as cooling towers lose water from evaporation. One alternative to prevent this would be to implement a radiative cooling system. More specifically, a system that utilizes the volumetric radiation emission from water to the night sky could be implemented. This thesis analyzes the validity of a radiative cooling system that uses direct radiant emission to cool water. A brief study on potential infrared transparent cover materials such as polyethylene (PE) and polyvinyl carbonate (PVC) was performed. Also, two different experiments to determine the cooling power from radiation were developed and run. The results showed a minimum cooling power of 33.7 W/m2 for a vacuum insulated glass system and 37.57 W/m2 for a tray system with a maximum of 98.61 Wm-2 at a point when conduction and convection heat fluxes were considered to be zero. The results also showed that PE proved to be the best cover material. The minimum numerical results compared well with other studies performed in the field using similar techniques and materials. The results show that a radiative cooling system for a power plant could be feasible given that the cover material selection is narrowed down, an ample amount of land is available and an economic analysis is performed proving it to be cost competitive with conventional systems. / Dissertation/Thesis / Excel Data with generated plots and some calcs / Raw Data / FTIR csv files for materials / FTIR generated images / IR camera images / Experimental setup images / M.S. Mechanical Engineering 2011

Light pollution is a problem that affects both living creatures as well as the perception of the night sky. As artificial lighting becomes more affordable and energy efficient, more and more lights are being used, further increasing the light pollution produced by us humans where cities with larger populations experience the largest amount of light pollution. There is however a knowledge gap in the field of light pollution regarding the possibility of a relationship between sky view factor and the brightness of the night sky. This study attempts to reduce that knowledge gap. By using cameras to take photos in different locations, the brightness of the night sky can be compared and together with the sky view factor of each location in can be determined if there exist such a relationship. Based on the results of this study, trends suggesting that this relationship exists emerges, however not to the extent that any definite conclusions can be drawn without further studies.

Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: A passive night-sky radiation cooling system consists of a radiation panel and a cold water storage tank. The stored cold water may be used to cool a room during the day time, particularly in summer. In this thesis a theoretical and mathematically sound simulation model is developed. An experimental set-up was constructed and subsequently used to show that the theoretical model effectively simulates the transient heating or cooling response of the system. It is shown that under South African conditions the typical heat emitting rate during the night is 55 W/m2. After the heat has been removed from the water, it is stored in a cold water tank from where it is circulated through a natural convector during the day time to absorb heat from the room. The experiment extracted a minimum of 102 W/m3 of heat from a 1.87 m3 galvanized steel room while a brick room with a volume of 120 m3 requires 22.7 W/m3. Additional to cooling, the system during the day, absorbed an average of 362 W of energy and heated 68 l of water from 24 °C to 62 °C within an 8-hour period. The system achieved similar results during winter conditions and the experiment confirms that the system is capable of operating without a control system. Therefore it is recommended that renewable energy-conscious designers pay more attention to the use of night-sky radiation cooling in future. / AFRIKKANSE OPSOMMING: en ’n koue water tenk. Die sisteem kan gebruik word om ’n vertrek gedurende die dag te verkoel, veral in die somer, deur gebruik te maak van die gestoorde verkoelde water. In hierdie tesis word ’n teoretiese en sinvolle wiskundige simulasie model ontwikkel. ’n Eksperimentele stelsel is gebou en vervolgens gebruik om te bewys dat die teoretiese model die veranderende verkoeling en verwarming van die stelsel effektief simuleer. Die tesis dui aan dat onder Suid Afrikaanse toestande daar ’n hitte vrystellings tempo van 55 W/m2 is gedurende die nag. Nadat die water verkoel is, word dit gestoor in die koue water tenk vanwaar dit deur ’n natuurlike konvektor sirkuleer en gedurende die dag warmte vanuit die vertrek onttrek. Die eksperiment het ’n minimum van 102 W/m3 warmte vanuit die galvaniseerde 1.87 m3 vertrek geabsorbeer, terwyl ’n baksteen vertrek van 120 m3, 22.7 W/m3 verkoeling benodig. Bykomstig tot die verkoelingstelsel verhit die sisteem 68 l water vanaf 24 °C to 62 °C gedurende ’n 8-uur periode in die dag, dus word 362Wenergie geabsorbeer. Die sisteem is ook getoets tydens winter toestande, die resultate was dieselfde as wat in die somer verkry is. Verder is daar ook bewys dat die sisteem sonder enige beheerstelsel kan funksioneer. Verder word daar aanbeveel dat hernubare energie bewuste ontwerpers in die toekoms meer aandag aan ruimte straling verkoeling skenk.

The PhD thesis deals with the theoretical evaluation of the potential use of night cooling techniques in condition of the Czech Republic. Mainly aims to evaluate the potential of night cooling, which uses the physical phenomenon of radiation against the night sky. This technique is widely used mainly in the dry and hot regions where there are the most suitable climatic conditions for this cooling method. The work is based on the current state of knowledge in the area of passive and low-energy cooling systems. These knowledges are applied to the conditions of Czech Republic and by using simulations of the energy, behaviour of the buildings explores the benefits in terms of improving of the internal microclimate and from the perspective of economy operation of conventional cooling equipment. In order to establish the benefits of night cooling on the operation of the building in the dynamically changing conditions, the modular simulation program TRNSYS was used, which is suitable for the analysis of energy systems of buildings and their behaviour. The results of simulation results were converted to thermal comfort parameters of the PMV and the PPD.

In the academic field of tourism, a relatively new type of tourism called Dark Sky Tourism is emerging. In this touristic field, there is a lack of studies focused on the individual tourist perspective. Therefore, this paper explores the perceived values of Dark Sky Tourism (DST). This study uses a deductive exploratory approach to understand the characteristics of DST in the context of experience value and perceived value and to connect it with two different value typologies. The data were collected through a netnographic research method by analyzing five different social media platforms. Subsequently, thematic analysis was utilized to analyze the data. The analysis resulted in five correspondent themes that were relevant throughout all of the collected data. These themes are as follows: (1) Aesthetic Significance, (2) Therapeutic Experiences, (3) Exploration and Curiosity, (4) Low-budget Appeal, and finally, (5) Nature and Heritage. The results of this study provide a holistic picture of what DST is all about and what individual Dark Sky Tourists value in DST. Future potential DST destinations can use this study to understand how to build an optimal DST experience.

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