6.7 Cost analysis

6.7 COST ANAL YSIS

In Table 10, the total cost of the solar heating system was utilised in this experiment to determine the project’s cost-effectiveness.

Table 10: Cost analysis

M aterial Cost

Solar air heater:

Chromadek sheeting R70,00 152mm x 38 Timber frame No cost 4mm thick clear glass R30,00 News Paper No cost Bubble wrap No cost Backing board No cost 5 Watt solar panel R90,00 1.5 Watt circulation fan R87,00 Fixing screws (50) R37,00 Wood glue (500ml) R45,00

Sub-total for solar air heater R359,00 Rock bed heat collector:

100-150mm Rock No cost Shutter board No cost 50mm Thick polystyrene No cost U-Pvc pipes R68,00 Fixing screws (50) R37,00 Wood glue (500ml) R45,00

Sub-total for rock bed R150,00 Total cost R509,00

The total cost for the solar air heater is R359,00, and the cost for the rock bed heat collector is R150,00. The total cost for the solar heating system is R509,00. The cost of the system is competitive with the commercial products available on the market.

CONCLUSION

• Chapter 7: Introduction • Recommendation • Opportunities for communities

7 INTRODUCTION

Chapter 7 discuss the recommendations of the solar heating system after completing the full experiment in Chapter 6. Furthermore, the chapter focus on the potential for further study. The chapter ends with the potential impact the system can have on low-income communities when the solar heating system is implemented successfully

7.1 RECOM M ENDATIONS 7.1.1 Heating system recommendation

Taking into consideration the results from Chapter 6, the following items are recommended for the heating system: It is recommended that –

• The enclosed system be used for space heating during the winter season as it proved to discharge the most sufficient heat. • The enclosed system be tested further to establish the possibility of seasonal charging. The results of section 6.2 showed a gradual increase in the minimum temperature from the rocks each day. • Alternative rocks sizes are tested to improve the efficiency of the heating system. • The heating system be tested on a large-scale experiment to determine its effectiveness on a housing unit.

7.1.2 Cooling system recommendations: The following items are recommended for the cooling system. It is recommended that-

• The ventilated cooling system be used for the implementation during the summer season as it proved to be the most efficient during this experiment. • Alternative rocks sizes be tested to improve the cooling system’s efficiency as smaller rocks can charge and discharge much quicker. • The ventilated cooling system be tested on a large-scale experiment to determine its effectiveness on a housing unit.

7.1.3 System refinement recommendations:

The system will require technical refinement to be used in practice. The following changes can be made to improve the quality and longevity of the system: • The system can be waterproofed to prevent any water to enter the system. • The glass panel be changed to a polymer material to prevent breakage. • The insulation material can be improved to reduce heat loss from the rock bed.

7.2 OPPORTUNITIES FOR COM M UNITIES

7.2.1 Local labour opportunities

Implementing the system on low-cost housing within communities can create new opportunities for local labour. Opportunities for the following trades and categories can arise by implementing this system: • Electrician: Installation of the solar panel, circulation fan, and power port. • Carpenter: Construction of the rock bed box and main frame of the solar air heater. • Plumber: Connection of circulation pipes on the system. • Contractors: Install the systems on housing units either as a retrofit or a new build. • Maintenance: Service provider to do routine checks on the systems installed in a community every month and fix the systems as required.

7.2.2 Local economy upliftment

To construct the solar heating/ cooling system, the material required will need to be sourced on a large scale. Similar to recycling plastic, glass, and paper within low-income communities, a new system can be developed whereby waste pickers source and locate second-hand materials required to construct the system. The materials can be sourced from dumpsites, redundant construction projects, existing buildings’ demolition, or off-cut material from existing construction projects.

The products can be sold to the contractors constructing the systems or the maintenance service provider requiring materials to fix the existing systems.The implementation of the solar heating/cooling system will not only impact the thermal comfort and living conditions of low-income communities. It can also create local opportunities for labour and entrepreneurial innovation. This will be able to uplift the economy of low-income communities and help the people to take matters into their own hands to improve their overall living conditions.

LIST OF FIGURES (All figures by Author unless referenced otherwise)

Figure 1: Front page: Nongoma informal settlement: KZN....................................................2 Figure 2: Typical illustration of proposed heating system experimental set-up during the winter season .....................................................................................................................3 Figure 3: Typical illustration of proposed cooling system experimental set-up during the winter season. ....................................................................................................................4 Figure 4: Map of South Africa and Gauteng .........................................................................7 Figure 5: Concept diagram drawing of solar air heater and rock bed heat collector. ............23 Figure 6: Concept diagram drawing of a solar air heater ....................................................24 Figure 7: Concept drawing of obstruction in solar air heater. ..............................................25 Figure 8: Concept drawing of rock bed ..............................................................................26 Figure 9: Concept model of complete solar air heating system to be tested during the experiment .......................................................................................................................27 Figure 10: Concept model: Exploded view of rock bed heat collector box ...........................28 Figure 11: Concept model: Exploded view of a solar air heater. .........................................29 Figure 12: Chromadek roof sheet & Figure 13: Obstacles in solar air .................................30 Figure 14: SA Pine timber frame for solar & Figure 15: SA Pine timber planks....................31 Figure 16: Glass panel ......................................................................................................31 Figure 17: Newspaper insulation & Figure 18: Bubble wrap insulation ................................32 Figure 19: Timber courier box ...........................................................................................33 Figure 20: Circulation fan ..................................................................................................33 Figure 21: Solar panel ......................................................................................................33 Figure 22: Complete solar air heater .................................................................................34 Figure 23: Off-cut shutter board & Figure 24: Construction of heat collector box .................35 Figure 25: Insulation in waste bin & Figure 26: Bulk insulation obtained .............................36 Figure 27: Insulation fixed to timber box ............................................................................36 Figure 28: Rocks from a construction site ..........................................................................37 Figure 29: Size of rocks obtained ......................................................................................37 Figure 30: Placement of U-PVC pipes ...............................................................................38 Figure 31: Inlet pipe to rock bed heat collector...................................................................38 Figure 32: Outlet from rock bed heat collector ...................................................................38 Figure 33: Psychrometer...................................................................................................41 Figure 34: Data logger ......................................................................................................42 Figure 35: Solar air heater outlet .......................................................................................43 Figure 36: Complete solar air heater .................................................................................43 Figure 37: Pilot study part 1 results ...................................................................................45 Figure 38: Solar heating system front view & Figure 39: Solar heating system side view ....46 Figure 40: Pilot study part 2 experiment results – Day 1 ....................................................47 Figure 41: Pilot study part 2 experiment results – Day 2 ....................................................47 Figure 42: Pilot study part 2 experiment results – Day 3 ....................................................48 Figure 43: Revised solar heating system & Figure 44: Insulation over exposed pipes .........50 Figure 45: Diagram of ventilated heating system ...............................................................53 Figure 46: Pipes of ventilated heating system ....................................................................54 Figure 47: Ventilated heating system experiment results – Day 1 .......................................55 Figure 48: Ventilated heating system experiment results – Day 2 .......................................55 Figure 49: Ventilated heating system experiment results – Day 3 .......................................56

Figure 50: Ventilated heating system experiment results – Day 4 .......................................56 Figure 51: Ventilated heating system experiment results – Day 5 .......................................56 Figure 52: Ventilated heating system experiment results – Day 6 .......................................57 Figure 53: Ventilated heating system experiment results – Day 7 .......................................57 Figure 54: Ventilated heating system experiment results – Combined 7 Days ....................58 Figure 55: Rock diagram of the ventilated system during daytime ......................................60 Figure 56: Rock diagram of the ventilated system during the night-time .............................60 Figure 57: Diagram of enclosed heating system ................................................................61 Figure 58: Pipes of enclosed heating system .....................................................................62 Figure 59: Enclosed heating system experiment results – Day 1 ........................................63 Figure 60: Enclosed heating system experiment results – Day 2 ........................................63 Figure 61: Enclosed heating system experiment results – Day 3 ........................................64 Figure 62: Enclosed heating system experiment results – Day 4 ........................................64 Figure 63: Enclosed heating system experiment results – Day 5 ........................................65 Figure 64: Enclosed heating system experiment results – Day 6 ........................................65 Figure 65: Enclosed heating system experiment results – Day 7 ........................................66 Figure 66: Enclosed heating system experiment results – Combined 7 Days......................66 Figure 67: Rock diagram of enclosed heating system ........................................................68 Figure 68: Diagram of ventilated cooling system ................................................................69 Figure 69: Solar heating system glazed .............................................................................70 Figure 70: Ventilated cooling experiment results – Day 1 ...................................................71 Figure 71: Ventilated cooling experiment results – Day 2 ...................................................71 Figure 72: Ventilated cooling experiment results – Day 3 ...................................................72 Figure 73: Combined Results: Ventilated cooling experiment – 3 Days ..............................72 Figure 74: Enclosed cooling system diagram: Daytime ......................................................74 Figure 75: Enclosed cooling system diagram: Night-time ...................................................74 Figure 76: Enclosed cooling experiment results – Day 1 ....................................................76 Figure 77: Enclosed cooling experiment results – Day 2 ....................................................76 Figure 78: Enclosed cooling experiment results – Day 3 ....................................................77 Figure 79: Combined Results: Enclosed cooling experiment – 3 Days................................77 Figure 80: Solar heating system application on newly built housing unit .............................81 Figure 81: Solar heating system application on an existing housing unit .............................82

LIST OF TABLES (All tables by Author unless referenced otherwise)

Table 1: Heat storage characteristics of rock (Eckhoff and Okos 2013: 4) ........................ 10 Table 2: Calculation for heat storage material required (Eckhoff and Okos 2013: 6).......... 11 Table 3: Optimum solar angles (Le Roux, 2019: 15). ....................................................... 12 Table 4: Integrating the main aim, sub problem and hypothesis ....................................... 15 Table 5: The researcher’s paradigm indicated on the model developed by Laubscher (2011:15) ....................................................................................................................... 18 Table 6: Summary of research styles .............................................................................. 19 Table 7: Summary of the research design ....................................................................... 20 Table 8: Total rock required for heat storage. .................................................................. 39 Table 9: Pilot study part 1 results .................................................................................... 44 Table 10: Cost analysis................................................................................................... 83

LIST OF REFERENCES

Boulic M., Wang Y., Phipps R., Plagmann M., Cunningham C., Theobald C., HowdenChapman P., Baker M. & Trompetter P., (2014). Improving health and well-being in low decile classroom with solar ventilation in New Zeeland environment, New Zealand Built Environment Research Symposium (NZBERS),vol. 4, p. 2.

Eckhoff S.& Okos,M., (2013). Suggestions on selecting and using thermal storage materials and facilities, Purdue University Cooperative Extension Service, vol. 1, pp. 1-10.

Fellows, R., & Liu, A., 2015, Research Methods for Construction, Construction & Architectural Engineering, vol. 4, published January 2015, pp. 21-28.

Government Gazette of 2019, National Environmental Management: Air quality Act, (2004). (Act no. 39 of 2004) Strategy to Address Air Pollution in Dense Low-Income Settlements, published May 2019, pp. 8-23.

Kottek, M., Grieser, J., Beck, C. & Rubel, F., 2006, World Map of the Köppen-Geiger Climate Classification Updated, Meteorologische Zeitschrift, published May 2006.

Le Roux, W., (2016). Optimum tilt and azimuth angles for fixed solar collectors in South Africa using measured data, Renewable Energy, Published October 2016, pp. 6-17

Lutzow J. & Mikiver C., (2020). Simulation of airborne transmission of infection in a confined space using an agent-based model. Degree project in technology: KTH Royal Institute of Technology, p.6.

Marongiu F., Soprani S., & Engelbrecht K., (2019). Modeling of high-temperature thermal energy storage in rock beds – Experimental comparison and parametric study, Applied Thermal Engineering, vol. 163, pp.1.

Moolman S. & Capes M., (2021). The price of water and electricity in South Africa, A tale of two tragedies, viewed 16 February 2021, from https://www.iol.co.za/news/opinion/the-priceof-water-and-electricity-in-south-africa-a-tale-of-two-tragedies-6f98fc9a-7c67-4aeb-936c1d9947428aa0.

Naicker N., Teare J., Balakrishna U., Wright C. Y. & Mathee A., (2017). Indoor temperatures in low cost housing in Johannesburg, International Journal of Environmental Research and Public Health, vol. 11, pp.1-2.

Richard, (2009). Thermosiphon Solar Air Heater with heat storage, Renewable Energy for the Poor Man, viewed 20 July 2020, from https://poormanguides.blogspot.com/2009/06/thermosiphon-solar-air-heater-with-heat.html. SABS & NRCS, (2011). Energy efficiency in buildings, South African National Standards, SANS 204:2011, pp.30.

Sicre B. & Baumann P., (2015). High-efficiency ventilation and heating systems by means of solar air collectors for industry building refurbishment, International Journal of Low-Carbon Technologies, vol. 2, pp.130-142.

Sözen A., Khanlari A., Tuncer A.D., Şirin C., Afshari F.&Güngör A., (2020). Wool packed solar air heater made with waste material, Empirical Investigation of Small Scale Aluminium, March 2020, pp.6-9.

The Housing Development Agency (HDA), (2017). South Africa: Informal settlement status, South Africa Research Report, viewed 20 July 2020, from http://www.thehda.co.za/uploads/files/HDA_Informal_settlements_status_South_Africa.pdf

Vyas S. & Punjabi S., (2014). Thermal performance testing of a flat plate solar air heater using optical measurement technique, Material Science, vol. 3, pp.1.

World Health Organization (WHO), (2020). Transmission of SARS-CoV-2: implications for infection prevention precautions, W orld Health Organization Scientific Brief, viewed 2 June 2021, from https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2implications-for-infection-prevention-precautions.