Taking into account that the use of renewable energy is of vital importance at present as the only way to avoid the depletion of fossil fuels and environmental pollution, it is necessary to put into practice the massive use of solar thermal energy for the water heating, having as a problem How to reduce the consumption of fossil fuels with the use of renewable energy sources? and as an objective to apply technology that responds to the use of this type of energy as a way of saving and environmental decontamination. This work consists of the assembly and economic-energy evaluation of the installation of vacuum tube solar systems for water heating in two communities on the Isle of Youth with similar characteristics.
Key words: Economy, solar thermal energy.
Summary
Considering that the use of the renewable energy is by vital importance as of the present moment like only road of avoiding the exhaustion of the fossil fuels and the environmental contamination is done necessary to put into practice the utilization of massive form of the thermic solar energy for the heating of water, having like problem How do we decrease the consumption of fossil fuels with the utilization of the sources of renewable energy? And as I confer an objective aspect to apply technology that they answer to the suchlike use of energy like road of saving and of environmental decontamination. This work consists of the set-up and evaluation economic energetic of the installation of solar systems of pipes to the you emptied for heating of water in two communities of the young's Island with similar characteristics.
Key words: Economy, thermic solar energy.
INTRODUCTION
The history of humanity has been inextricably linked to energy consumption. Technological development and social welfare imply greater energy consumption worldwide, accentuating the greater energy consumption in industrialized countries, the so-called northern part of the world, thus surpassing the consumption rates of developing countries named as those of the south.
The consumption of natural gas for electricity generation is expected to continue to increase, representing 30% of global electricity generation in 2025.
In Cuba in 2001, of the total electricity generated, 79% corresponded to oil generation, and 17% to sugarcane biomass generation (2).
The increasing consumption of energy will not be able to be satisfied by the so-called traditional sources based on fossil fuels: coal, gas and oil, so these sources will have to be gradually replaced by other sources, which in turn are renewable.
As stated in Chapter VIII, in guideline 247 of the Economic and Social Policy, approved in the VI Congress of the PCC, it consists of promoting the use of different renewable energy sources.
Based on the problems presented, the following scientific problem is formulated.
- How to reduce the consumption of fossil fuels with the use of renewable energy sources?
In order to resolve this, the following general objective is exposed :
- Apply technology that responds to the use of solar thermal energy as a means of saving and environmental decontamination throughout the territory.
The research is based on the following hypothesis:
- If a technology for water heating using solar thermal energy is applied, then it will improve the saving of fossil fuel consumption and pollution of the environment.
In the development of the research, theoretical and empirical methods were used that integrate techniques and instruments of various kinds. Among the theoretical methods used are the analysis and synthesis of the information obtained from the specialized literature and the consultation of experts on the topics covered; the inductive-deductive for the analysis of the process; the systemic-structural to analyze the parts and interrelationships of the process and the modeling for the conception of the proposal made. The empirical methods used are related to psychosocial instruments for information search, expert judgment and statistical methods. Among them the observation of processes, surveys, unstructured interviews with managers and specialists, application of checklists and group work techniques.
DEVELOPING
1.1.- World energy consumption
Most of the energy consumption is based on fossil fuels, with many differences between countries. The US alone consumes 25% of the world total. Developed countries consume 80 times more than underdeveloped countries. Only a quarter of the world population consumes ¾ parts of all energy.
1.2.-Fuel reserves.
With the exception of nuclear energy, energy sources come from the Sun, according to the accumulation time can be classified into: Snapshots: PV (fractions of seconds) and solar thermal (less than 1 hour). Contemporary: wind (3 days), hydro (≤ 1 year), biomass (several years) and wood (∼10 years). Fossils: coal (over 100,000 years old), oil and gas (over 1 million years old).
In relation to nuclear energy, environmental pollution drastically decreases. Much has been written about environmental problems. The “concern” has increased a lot but the “occupation” of the problem has not increased as much, 5.6 109 tons are added to the atmosphere each year. metric carbon in the form of CO2, 50% responsible for global warming (greenhouse effect). The most polluting sector in the world is energy (57%). In the US, electricity companies shed more than 400 million tons. of carbon to the atmosphere per year in the form of CO2 (8% worldwide), more than the total energy consumed by Japan, or any European country, or all of Latin America combined. Total CO2 emission in the US (in all sectors) is much higher (6.4 million tons / year) and poses a slight decrease in future emissions.
1.3-Energy indicators.
There are two types of energy indicators, (1) Indicators that follow activities that manage energy use, for example, the amount of industrial production, the tons / kilometer traveled or the number of electrical appliances per person.
(2) The indicators that govern the development of energy intensity, for example, energy / passenger-Km. or energy / value added in an industrial branch.
- Energy intensity.
It is the one that measures the productivity of the economic process. The economic development of a country is based on energy production, which plays a predominant role for the sustainable economic impulse, but it is also a contributing factor in air pollution. The future impact of the energy sector on the environment depends largely on the ability to create energy policies, to integrate environmental issues well. One way of integration is based on the management of energy intensity.
The energy intensity shows us how much energy is required to generate a unit of GDP, how much is consumed to move a vehicle, quantity per dwelling, quantity per inhabitant, quantity by type of service or industry, etc. of time. For the calculation of the intensities, it is required to have an energy balance that indicates the end use of it, to which sectors of the economy it is directed and what are the consumption patterns.
1.4- Renewable Energies.
All forms of renewable energy are valid. Some of them exist only in specific places such as geothermal, hydroelectric and wind. In relation to Cuba, the most promising are: biomass, solar thermal, wind (limited) and photovoltaic, the latter form of energy.
Cuba is subject to extreme dependence on oil, both for transportation and for the generation of electricity, based on a distribution of thermoelectric oil plants, the direct component of solar radiation that ranges between 65 and 80 is not used % intensity
1.5-Solar energy.
As we generate energy that comes to us "daily" from the Sun (instantaneous or contemporary sources), discarding fossil or non-solar sources helps the natural thermodynamic balance Sun-earth. Last form of energy, reason for this draft program, of course should be framed as part of a comprehensive and diverse energy strategy as possible, in accordance with the most rational exploitation available.
1.6-Cost of energy.
Energy costs are very conventional and circumstantial. What is the price of what nature, by the way, accumulated with extremely low efficiency, over millions of years? How much does it cost to recover the polluted atmosphere? How much does spent oil cost (or will it cost)? How much does it cost to correct an altered ecosystem? How much does it cost to cure or treat sick people due to contamination? We saw that the greatest responsibility lies with industrially developed countries.
Many poor countries have to spend more than half of their meager foreign exchange buying fuel, only the installation of 1 meter of electric line costs from $ 20.00 to $ 25.00.
As long as energy is treated only as a "business" at the international level, irrationality will prevail and there will be no solution.
One aspect to include in the strategies would be the decrease in energy consumption of household appliances, for example: refrigerator, from 350 to 50 Kwh / year; freezer, from 500 to 100 Kwh / year; washing machine from 400 to 115 Kwh / year; etc.
1.7- In the framework of the energy revolution in Cuba, this work was carried out in the Isle of Youth considering two scenarios to carry out energy efficiency tests in the use of Chinese solar vacuum tube heaters:
Scenario 1, a set of 7 buildings in the Industrial Zone distribution, Gerona, with a total of 126 apartments, with 126 solar heaters installed and started up at the end of December 2007. Two meter total meters were located, one in each feeder at the output of each of the two distribution transformers that supply the 7 buildings.
Scenario 2, a set of 3 buildings from the Abel Santamaría district, each with 40 apartments (120 clients), which did not have solar heaters installed. In each building a totalizing meter was placed in the entrance connection.
To collect the information, electronic meter meters similar to a network analyzer were located, capable of storing the demand log in memory every 15 minutes with the possibility of extracting it to a laptop.
The method used is by comparing the measurements in two selected scenarios with similar characteristics and customer concentration, differentiated only by the solar heater, in order to discriminate the effect of temperature variation that causes a different behavior in consumption and in the demand of the residential sector.
The heater installation measurements span Business and Non-Business days (Saturday and Sunday) from December 1 to December 21, 2007.
Measurements after heater installation and commissioning span Business and Non-Business days from January 5 to January 23, 2008.
2.-EVALUATION OF THE IMPACT OF CHINESE VACUUM TUBE SOLAR HEATERS ON RESIDENTIAL CLIENTS OF THE ISLAND OF YOUTH.
The average daily savings for a customer who has a Model LPPCA47-1514-42 ALF vacuum tube solar heater installed. RPChina (90 liters of storage tank and 1.1 square meter of solar collection area), is:
0.9 kWh on Non-Business Days and
0.8 kWh on Business Days .
It represents 25 kWh less per month of average consumption per customer.
The average number of people per client in this scenario with 126 apartments is 4, that is, the daily per capita saving is 208 Watt-hours.
By installing 21,000 heaters on the Island, 17.5 MWh is saved daily, which could electrify 2,060 new homes on the Isle of Youth.
2.2.-RESULTS AND DISCUSSION
The results of the survey to 118 clients of this scenario to know the means used for the heating of water before the assembly and start-up of the solar heaters were as follows:
With corkscrew: 54.2%
With electric burner: 30.5%
With rice cooker: 1.7%
With queen pot: 1.7%
With gas: 2.5%
A total of 316 people (75.4% of the total) reported that they used hot water for bathing. In a survey carried out by the OBE, it was found that 90.7% of the people interviewed regularly use the available hot water for bathing.
This service begins to be used in other activities such as defrosting and preparing food, scrubbing, shaving, washing hair, washing clothes, cleaning, etc., which people express with satisfaction of the comfort that this represents, speed and saving electricity, time and soaps and detergents.
Table 1
Decrease in average daily consumption x customer in kWh due to the introduction of the heater
| Non-working days | Weekdays | ||||||
| Before | After | Differ. | Before | After | Difference | ||
| With solar heater
Scenario 1 |
10.0 | 8.5 | -1.5 | 8.7 | 7.5 | -1.2 | |
| Without solar heater.
Scenario 2 |
9.2 | 8.4 | -0.6 | 7.9 | 7.5 | -0.4 | |
| Daily savings
by the heater |
Net
(Scenario 1-2) |
-0.9 | Net
(Scenario 1-2) |
-0.8 | |||
| Savings per month
per customer |
9.0 | 16.0 | 25.0 kWh / month | ||||
| Impact for the 21 thousand clients of the Isle of Youth | 525 MWh / month | ||||||
| In 1 million clients in Cuba | 25 GWh / month |
Table # 2
Maximum demand reduction provided by an average customer in KW.
| Non-working days | Weekdays | ||||||
| Before | After | % | Before | After | % | ||
| With solar heater
Scenario 1 |
0.824 | 0.618 | 0.750 | 0.796 | 0.683 | 0.858 | |
| Without solar heater.
Scenario 2 |
0.693 | 0.650 | 0.939 | 0.750 | 0.740 | 0.987 | |
| % reduction
per heater |
Net
(Scenario 1-2) |
-0.189 | Net
(Scenario 1-2) |
-0,128 | |||
| Impact on reducing maximum demand by introducing a heater | |||||||
| Non-working days | Weekdays | ||||||
| Kw. reduction
prom x customer |
Kw. | 0.156 | 0.102 | ||||
| Impact for 21 thousand clients on Juv Island. | MW | 3.3 MW at the Peak | 2.1 MW at the Peak | ||||
| Impact for
1 million clients in Cuba |
MW | 156 MW at the Peak | 102 MW at the Peak |
Demand in rush hour decreases 18.9% on Non-Business days and decreases 12.8% on Business days.
The Island has a maximum demand of 19 MW and the installed generation capacity is 31.05 MW including 1.65 MW from the wind farm.
An average availability of 75% is estimated, representing 23.2 MW available, therefore the maximum demand and availability ratio is today 83%. By installing 21,000 solar heaters, the previous ratio would improve to 74%, that is, an increase in coverage of 26%.
HOT WATER TEMPERATURE VALUES AVAILABLE AT THE HOUSING DELIVERY POINT
| Day | Schedule | Temp.
Ambient |
Difference | Temp.
Water outlet |
Difference |
| 01/21/08 | Dawn | 21 ºC | 2 ºC | ºC | 4 ºC |
| Sunset | 23 ºC | 47 ºC | |||
| 43 01/22/08 | Dawn | 24 ºC | -1 ºC | 49 ºC | 5 ºC |
| Sunset | 23 ºC | 54 ºC | |||
| 01/23/08 | Dawn | 24 ºC | 57 ºC |
On average, the temperature is 50 ºC in the mornings and 55 ºC in the afternoons, although it can reach higher values as on January 23, good weather with clear skies and good solar lighting.
The average daily consumption for the introduction of the heater decreases 1 kWh on Non-Business Days and 0.5 kWh on Business Days.
Demand in rush hour is reduced by 16.5% on Non-Business days and by 13.0% for Business days.
CONCLUSIONS
At the end of the investigation, the following conclusions are reached:
- It has been shown that the application of this technology is one of the most important ways of saving energy and environmental decontamination. The use of the solar heater in the seven facilities of the Isle of Youth reaffirms the feasibility of its generalization. in residential and business sectors. The application of this energy allows us to:
- Formulation of coherent energy strategies. Use of planning tools and techniques for sustainable development. Formulate energy policies. Achieve significant savings for the National Economy.
RECOMMENDATIONS.
- Generalize the technology of the use of solar thermal energy as an indispensable source of savings to the entire country as conditions permit. The country's leadership should strategically project the massive use of this energy in all sectors of the economy where possible, for the incomparable benefits and as an important way of energy saving and as well as its contribution to the improvement of the environment by not releasing toxic substances in its generation.
BIBLIOGRAPHY.
- Brigham, Eugene F. and Gapenski, Louis C., 1994. Financial Management, The Dryden Press Publishing. Brigham, Eugene F., 1980. Fundamentals of financial management, The Dryden Press. Leiva Valdespino, Ing. Alexander. Energy, Environment and sustainability. Chapter I alPuerta Fernández, Dr.C. Juan Francisco. 2004. Economy and energy management. Course 03 - 04. Chapters I alUrda Bordoy, Dr.C. Marcos O. Management of CITMA projects. Chapter
