- TITLE:
SYNTESIS AND SIMULATION OF PRECODER FROM BINARY NRZ TO HDB3 CODE
- AUTHOR(S):
B. Karapenev
- ABSTRACT:
This paper presents the essence of the primary binary codes of the digital signal and also of quasi-ternary AMI and HDB3. A block and structural-functional diagram of precoder from binary NRZ to HDB3 code are presented and described in detail. A circuit (model) of precoder with TTL integrated circuits (ICs) has been synthesized. The obtained simulation results are shown using Electronics Workbench Pro software.
- TITLE:
EFFICIENCY OF VACUUM-HEAT PIPE SOLAR COLLECTOR
- AUTHOR(S):
V. M. Petkov
- ABSTRACT:
The instant and integral characteristics of vacuum-heat pipe solar collector with different design have been investigated. The variation of instant efficiency of solar collector with solar heat flux and temperature of the intermediate coolant during the day hours have been presented.
- TITLE:
EFFICIENCY OF FLAT SOLAR COLLECTOR WITH FINNED HEAT PIPES
- AUTHOR(S):
V. M. Petkov
- ABSTRACT:
The influence of the fin width, degree of filling in of the heat pipe and the kind of the glass cover on the instant characteristics of the flat solar collector with finned heat pipes has been investigated. The variation of the instant efficiency of the solar collector during the day hours, with solar heat flux and temperature of the intermediate coolant is presented.
- TITLE:
EFFICIENCY OF PROTRACTED FLAT SOLAR COLLECTOR WITH FINNED TUBES
- AUTHOR(S):
V. M. Petkov
- ABSTRACT:
The instant and integral characteristics of protracted flat solar collector with finned tubes have been investigated. The variation of instant efficiency of solar collector with solar heat flux and temperature of the intermediate coolant during the day hours have been presented.
- TITLE:
PERFORMANCE EVALUATION OF LAMINAR FULLY DEVELOPED FLOW THROUGH TRAPEZOIDAL AND HEXAGONAL DUCTS SUBJECTED TO H1 BOUNDARY CONDITION. PART 2
- AUTHOR(S):
V. M. Petkov, V. D. Zimparov
- ABSTRACT:
Extended performance evaluation criteria (ExPEC) have been used to assess the performance characteristics of single-phase fully developed laminar flow through bundle of tubes with trapezoidal and hexagonal ducts. The bundle with circular tubes has been used as a reference heat transfer unit. The H1 boundary condition has been selected as thermal boundary condition. The performance characteristics
of the heat unit with non-circular tubes have been evaluated and compared to those of the reference unit for different objectives and constraints imposed. As a common constraint, the hydraulic diameter of the non-circular duct has been specified. The results showed that only in the case VG-1 the benefit can be obtained for the values of the irreversibility ratio.
