scholarly journals Operation analysis of primary and secondary networks of distributed solar heating system in Tibet

2021 ◽  
Vol 329 ◽  
pp. 01079
Author(s):  
Chengpeng Liu

Tibet is located in a high cold and high altitude area. Heating in winter is an important problem to be solved urgently, and the distributed solar heating system provides a solution for the efficient and clean utilization of energy in this area. Through the test and commissioning of the distributed solar heating system with supplementary combustion in Tibet, the operation characteristics of the heating system are analyzed from the temperature changes of the primary network and the secondary network. The research results can provide technical support for the application and promotion of the solar distributed heating system with supplementary combustion in Tibet.

1974 ◽  
Vol 28 (5) ◽  
pp. 732-738
Author(s):  
Adam Chrzanowski ◽  
Nicholas Canellopoulos

The redefinition has been considered as a necessary step to improve the primary control network, which at the present does not satisfy the accuracy requirements of all the users. In view of the existing distortions in the primary control and in view of the forthcoming redefinition, the user who is involved in a densification survey faces the following questions: 1) how to perform the adjustment of the secondary networks in order to be independent of the distortion of the primary network, 2) how to take the advantage of those parts of the primary network that satisfy his requirements. If the two questions are answered, one has to solve a problem on how to transform, in the best way, the established secondary network into the redefined coordinates system. The authors try to give an answer to those questions considering the following four cases: 1) the relative accuracy between the higher order points is much better than the relative accuracy of the same points belonging to the densification network; 2) both primary and densification methods have the same accuracy; 3) the relative accuracy of the higher order network is worse than the corresponding of the densification network; 4) the relative accuracy of the points of the higher order network is unknown. The authors advocate that a free adjustment and a fitting method should answer the problem.


2018 ◽  
Vol 8 (12) ◽  
pp. 2486 ◽  
Author(s):  
Eylem Erdogan ◽  
Sultan Çolak ◽  
Hakan Alakoca ◽  
Mustafa Namdar ◽  
Arif Basgumus ◽  
...  

In this work, we examine the interference alignment (IA) performance of a multi-input multi-output (MIMO) multi-hop cognitive radio (CR) network in the presence of multiple primary users. In the proposed architecture, it is assumed that linear IA is adopted at the secondary network to alleviate the interference between primary and secondary networks. By doing so, the secondary source can communicate with the secondary destination via multiple relays without causing any interference to the primary network. Even though linear IA can suppress the interference in CR networks considerably, interference leakages may occur due to a fast fading channel. To this end, we focus on the performance of the secondary network for two different cases: (i) the interference is perfectly aligned; (ii) the impact of interference leakages. For both cases, closed-form expressions of outage probability and ergodic capacity are derived. The results, which are validated by Monte Carlo simulations, show that interference leakages can deteriorate both system performance and the diversity gains considerably.


2019 ◽  
Vol 50 (7) ◽  
pp. 659-670 ◽  
Author(s):  
Jieyuan Yang ◽  
Jinping Li ◽  
Rong Feng

Author(s):  
Nguyen Hong Giang ◽  
Vo Nguyen Quoc Bao ◽  
Hung Nguyen-Le

This paper analyzes the performance of a cognitive underlay system over Nakagami-m fading channels, where maximal ratio combining (MRC) is employed at secondary destination and relay nodes. Under the condition of imperfect channel state information (CSI) of interfering channels, system performance metrics for the primary network and for the secondary network are formulated into exact and approximate expressions, which can be served as theoretical guidelines for system designs. To verify the performance analysis, several analytical and simulated results of the system performance are provided under various system and channel settings.


2015 ◽  
Vol 121 ◽  
pp. 1356-1364 ◽  
Author(s):  
Tao Li ◽  
Yanfeng Liu ◽  
Dengjia Wang ◽  
Kaifeng Shang ◽  
Jiaping Liu

1997 ◽  
Vol 19 (2) ◽  
pp. 163-172
Author(s):  
ARMEN HOVSEPIAN ◽  
MARK KAISER
Keyword(s):  

1994 ◽  
Vol 116 (2) ◽  
pp. 88-93 ◽  
Author(s):  
E. Hahne ◽  
M. Hornberger

At Stuttgart University, a solar heating system for an office building with laboratories and lecture rooms was installed in 1985. It consists of 211 m2 of unglazed solar collectors, a 1050 m3 water-flooded pebble bed heat store, and a heat pump. Heat can be supplied to the store from the solar collectors or from a power station (as waste heat). The whole system has worked successfully for five years under varied strategies. In the first two heating periods, the heating strategy was aimed to collect as much solar energy as possible. Thus, about 60 percent of the heat demand could be covered by solar energy; but the yearly heat pump coefficient of performance (COP) was only around 2.76. With an improved heat pump, a monthly COP of 3.6 was obtained. Heat losses from the storage amounted to about 20 percent.


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