Abstract: A lower consumption of thermal energy will
contribute not only to a reduction in the running costs, but also in the
reduction of pollutant emissions that contribute to the greenhouse
effect. Cogeneration or CHP (Combined Heat and Power) is the
system that produces power and usable heat simultaneously by
decreasing the pollutant emissions and increasing the efficiency.
Combined production of mechanical or electrical and thermal energy
using a simple energy source, such as oil, coal, natural or liquefied
gas, biomass or the sun; affords remarkable energy savings and
frequently makes it possible to operate with greater efficiency when
compared to a system producing heat and power separately. This
study aims to bring out the contributions of cogeneration systems to
the environment and sustainability by saving the energy and reducing
the emissions. In this way we made a comprehensive investigation in
the literature by focusing on the environmental aspects of the
cogeneration systems. In the light of these studies we reached that,
cogeneration systems must be consider in sustainability and their
benefits on protecting the ecology must be investigated.
Abstract: Greenhouses offer us suitable conditions which can
be controlled easily for the growth of the plant and they are made by
using a covering material that allows the sun light entering into the
system. Covering material can be glass, fiber glass, plastic or another
transparent element. This study investigates the solar energy usability
rates and solar energy benefitting rates of a semi-spherical (modified
arch) type greenhouse system according to different orientations and
positions which exists under climatic conditions of Bayburt. In the
concept of this study it is tried to determine the best direction and
best sizes of a semi-spherical greenhouse to get best solar benefit
from the sun. To achieve this aim a modeling study is made by using
MATLAB. However, this modeling study is run for some determined
shapes and greenhouses it can be used for different shaped
greenhouses or buildings. The basic parameters are determined as
greenhouse azimuth angle, the rate of size of long edge to short and
seasonal solar energy gaining of greenhouse. The optimum azimuth
angles of 400, 300, 250, 200, 150, 100, 50 m2 modified arch
greenhouse are 90o, 90o, 35o, 35o, 34o, 33o and 22o while their
optimum k values (ratio of length to width) are 10, 10, 10, 10, 6, 4
and 4 respectively. Positioning the buildings in order to get more
solar heat energy in winter and less in summer brings out energy and
money savings and increases the comfort.