1. “Feasibility analysis of a hybrid photovoltaic/thermal cogeneration system for domestic applications” Eduardo Ruiz-Casanova, Carlos Rubio-Maya, Ana Laura Soto-Sánchez, Crisanto Mendoza-Covarrubias and Jesús Martínez-Patiño November 2016, Phoenix, AZ,USA

2. Introduction System description Simulation procedure Economic analysis
CONTENT
Introduction
System description
Simulation procedure
Economic analysis
Results
Conclusions

3. Renewable energies and new technologies as a viable solution
INTRODUCTION
Fossil fuels: Environmental impact, higher costs and depletion of its deposits
Renewable energies and new technologies as a viable solution

4. INTRODUCTION SOLAR ENERGY
Solar energy is one of the most promising sources of alternative energy, with a wide research done over the past decades, with the aim of improving its efficiency and economic viability.
Thermal, consist in utilize the solar radiation for heat a fluid.
Photovoltaic, consist in the direct transformation of solar energy in electrical energy by means of the photoelectric effect.

5. INTRODUCTION A PV CELLS ISSUE
PV cells make use of only a small amount of solar energy, having a low energy conversion efficiency. The photoelectric conversion efficiency of solar cells commercially available is between 6-25% under optimum operating conditions depending on the type of technology. This means that a large fraction of energy is not utilized, and is absorbed by the cells, causing an increase in its temperature. The temperature rise has a negative effect on the cells, as it reduces its conversion efficiency.
Temperature effect over a Power and Voltage generated by typical PV cell

6. INTRODUCTION HYBRID PV/T SYSTEMS
One way to reduce the cells temperature is eliminating waste heat mounting heat extraction devices. If the extracted heat is used for any practical application, the result is a combined device that produce electricity and heat simultaneously from solar radiation. The new device is called hybrid PV/T collector.
Using this type of collectors has two advantages:
Removing residual heat from the PV panel, it is possible to reduce operating temperature, increasing the efficiency of the PV module.
This extracted heat can be used for any application such as water heating, heating, cooling, etc.
To take advantage of the electrical and thermal energy produced by this collector other elements are attached forming a hybrid PV/T system.

7. Three-dimensional model of PV/T collector
SYSTEM DESCRIPTION
Three-dimensional model of PV/T collector 1
Cover glass 2
Polycrystalline photovoltaic sheet of 250 W 3
Copper sheet 4
Copper grid-type piping 5
Expanded polystyrene side insulation 6
Expanded polystyrene rear insulation 7
Aluminum frame

8. SIMULATION PROCEDURE DATA COLLECTION Climatic Data
The Typical Meteorological Year (TMY), is used in a wide range of simulation programs instead of using weather data of several years which can vary widely.
For this work, using the Meteonorm software, a file with the TMY for the city of Morelia, Michoacan, Mexico (Latitude: 19°42′02″ N, Longitude: 101°11′03″ O ) was generated.

9. SIMULATION PROCEDURE DATA COLLECTION Consumption Data (Electricity)
Electricity consumption data was obtained through direct measurements on a typical home by using a power quality analyzer registering data every 10 minutes during one year. Characteristics of electric power supply are: 110 V and 60 Hz, able to manage up to 3 kW. The building is a two-story low-income household with 90 m2, where 4 people live on a daily basis.

10. SIMULATION PROCEDURE DATA COLLECTION Consumption Data (DHW)
It was obtained Information about the consumption of DHW for a typical Mexican household of four inhabitants along a typical day for each month of the year, taking into account activities such as showering, dishwashing and laundry. Using this information, was created a profile of hot water consumption of a typical day for each month. The total daily consumption considered in this work was 45 L/person, totaling 180 liters per day at 60 ºC.

11. SIMULATION PROCEDURE
TRNSYS MODELING

12. ECONOMIC ANALYSIS CASH FLOWS
It is estimated that cash flows arising from the implementation of the system are composed of:
Investment costs (Cinv)
Operating costs and maintenance (CO&M), and
Annual savings (Csav)
Investment costs were determined by the sum of the costs of individual elements of the system.
Since there is a huge variation in prices, it was decided to determine a range from the lowest (optimistic case) to the highest (pessimistic case) price found. In practice, operating costs and maintenance are discarded. As for the annual savings they were determined by adding the savings in electricity (Aelec) and savings in buying LP gas (Agas).

13. ECONOMIC ANALYSIS ECONOMIC INDICATORS Simple Payback Period (SPP)
Net Present Value (NPV)
Internal Rate of Return (IRR)

14. RESULTS SIMULATION OF PROPOSED PV/T SYSTEM
It was estimated that the proposed system will generate annually and kWh of thermal and electrical energy respectively. Incident solar energy on the collector indicates a total of kWh. From these data both annual thermal and electrical efficiencies were calculated, having a 45.42% for thermal efficiency and 12.07% for the electrical efficiency.
The system contributes with 51.15% of thermal energy for heating water, and 29.23% of the electricity required by the household.
Monthly produced energy thru a year (Heat and Electricity) with the incident irradiation.

15. RESULTS ENERGETIC COMPARATIVE OF THREE DIFFERENT SYSTEMS
Heat
Electricity
Total
Efficiency
[kWh]
[%]
PV/T C
393.57
57.48
PV/T U
453.56
44.74 PV -
423.96
13.00
The system that produced more heat was the proposed Covered (PV/T C).
Uncovered system (PV/T U) produces more electrical energy than the other ones.
The efficiency of the pure PV system is 13% while the efficiency of the PV/T Covered and PV/T Uncovered systems are higher 44.48% and 31.74% respectively.

16. RESULTS ECONOMIC ANALYSIS *Amounts in Mexican Pesos SYSTEM PV/T C
PV/T U PV
CASE
OPT
PES
Cinv [$]
16650
24750
15650
23750
8250
13500
Agas [$/yr]
2035
1381 -
Aelec [$/yr]
479
546
514
Csav [$/yr]
2514
1927
SPP [yrs]
6.62
9.84
8.12
12.32
16.05
26.26
NPV [$]
2129
-2046
-1260
-9360
-4413
-9663
IRR
14% 8%
10.07%
5.13%
2.19%
-2.47%
*Amounts in Mexican Pesos

17. CONCLUSIONS
Because of its location, Mexico has great potential for harnessing solar energy.
For this specific case, with only 1.55 m2 of collector, the proposed system can cover 51.15% of domestic water heating demand and % of the electricity demand. The system reaches a total energetic efficiency of 57.48%, while a PV system with the same collection area reaches 13% for the same conditions. It can be seen that a hybrid system takes better advantage of energy than a PV system.
Analyzing economic indicators, it can be confirmed that proposed system is viable in an optimistic case.
Using hybrid PV/T systems is possible to increase the rational energy use, reduce space for installation of solar devices and improve economic performance.
The results allow to determine under what conditions a hybrid PV/T system is expected to have a technical and economic feasibility. From the technical point of view, the provided results give assurance that a system similar to the characteristics of the proposed will have a good performance and feasibility to implement in a practical level.

18. THANKS! ¡GRACIAS POR SU ATENCIÓN!
GREEN-ER Group of Energy Efficiency and Renewable Energy
Contact: Eduardo Ruiz-Casanova