How to Evaluate the Operating Performance of Mid-Deep Geothermal Heat Pump Systems (MD-GHPs): A Study on a Multistage Evaluation Index System DOI Open Access
Chenwei Peng, Jiewen Deng, Siwen Li

et al.

Sustainability, Journal Year: 2024, Volume and Issue: 16(22), P. 10097 - 10097

Published: Nov. 19, 2024

Mid-deep geothermal heat pump systems (MD-GHPs) use mid-deep borehole exchangers (MDBHEs) to extract from the energy at a depth of 2–3 km, and have been used for space heating in China over last decade. This paper proposes comprehensive multilevel evaluation-index system analyze evaluate performance MD-GHPs. The evaluation index consists target layer, criterion an where layer is subdivided into six aspects includes 26 specific indices, reflecting resources, transfer MDBHEs, efficiency systems, building demand, grid dynamic response capability, energy-saving economic benefits. Then, based on both expert survey results case study data, entropy weight method analytic hierarchy process are integrated determine indicator coefficients among comprehensively considering subjective objective analyses. Furthermore, fuzzy model conducted integrate these weighted indices multi-criteria MD-GHP performance. Finally, proposed was applied practical four projects, returning scores 61.56, 58.33, 72.73, 78.41. These evaluations enable overall assessment MD-GHPs, technical weaknesses offering optimization guidance design operation.

Language: Английский

A Novel Heat Pulse Method in Determining “Effective” Thermal Properties in Frozen Soil DOI Creative Commons
Xiaolong Wu, Ying Zhao

Water Resources Research, Journal Year: 2024, Volume and Issue: 60(12)

Published: Dec. 1, 2024

Abstract Accurate and fast measurements of thermal properties are frequently required for characterizing the heat‐water dynamics in frozen soil. Measuring soil without inducing ice thaw has proven challenging with conventional heat pulse (HP) methods. In this study, based on an Infinite Line Source (ILS) semi‐analytical model that applies a constant temperature lower than freezing point at source to prevent initiation soil, we propose novel HP‐based approach measure properties, applicable temperatures below or above 0°C. Laboratory experiments numerical modeling were utilized validate applicability optimization strategies measurement. We found proposed effectively maintained maximum spatial therefore estimated bulk quartz sand contents. An optimized measurement strategy was monitor variations 2–4 cm away from center probe after 60 s. This progress can largely facilitate determination multi‐phase ‐component such as conductivity, flux, content cold areas across science, hydrology, engineering, climate science.

Language: Английский

Citations

12
Temperature Reduction Characteristics of Coal with Different Moisture Contents During Cryogenic Treatment DOI
Siqi Zhang, Zhaofeng Wang,

Xingying Ma

et al.

Natural Resources Research, Journal Year: 2024, Volume and Issue: 33(6), P. 2771 - 2787

Published: July 18, 2024

Language: Английский

Citations

2
Overlooked biocrust impacts on surface soil thermal properties: Evidence from heat‐pulse sensing on large volume samples DOI
Junru Chen, Bo Xiao, Joshua L. Heitman

et al.

European Journal of Soil Science, Journal Year: 2024, Volume and Issue: 75(6)

Published: Jan. 1, 2024

Abstract Biocrusts are a critical surface cover in global drylands, but knowledge about their influences on soil thermal properties still lacking because it is quite challenging to make accurate property measurements for biocrust layers, which only millimetres thick. In this study, we repacked layers (moss‐ and cyanobacteria‐dominated, respectively) that had the same material as original intact biocrusts was more homogeneous thicker. The conductivity ( λ ), heat capacity C ) diffusivity k of were measured by pulse (HP) technique at different mass water contents θ m ratios W t differences between analysed. Our results show substantially alter surface. average moss (0.37 −1 K cyanobacteria (0.90 reduced 63.0% 10.3% compared with bare (1.00 respectively. Edge effects including loss evaporation caused be underestimated, overestimated. significant p <0.001), except biocrusts, not = 0.379). Specifically, volumetric content v range 0 20%, underestimated 59.1% 61.8%, respectively, overestimated 23.9% biocrusts. 15.8% 79.2%, 34.8% 30%. Typically, difference increased rises new provide evidence previously misjudged due measurement limitations imposed limited thickness when situ. likely regulating temperature drylands than assumed.

Language: Английский

Citations

1
How to Evaluate the Operating Performance of Mid-Deep Geothermal Heat Pump Systems (MD-GHPs): A Study on a Multistage Evaluation Index System DOI Open Access
Chenwei Peng, Jiewen Deng, Siwen Li

et al.

Sustainability, Journal Year: 2024, Volume and Issue: 16(22), P. 10097 - 10097

Published: Nov. 19, 2024

Mid-deep geothermal heat pump systems (MD-GHPs) use mid-deep borehole exchangers (MDBHEs) to extract from the energy at a depth of 2–3 km, and have been used for space heating in China over last decade. This paper proposes comprehensive multilevel evaluation-index system analyze evaluate performance MD-GHPs. The evaluation index consists target layer, criterion an where layer is subdivided into six aspects includes 26 specific indices, reflecting resources, transfer MDBHEs, efficiency systems, building demand, grid dynamic response capability, energy-saving economic benefits. Then, based on both expert survey results case study data, entropy weight method analytic hierarchy process are integrated determine indicator coefficients among comprehensively considering subjective objective analyses. Furthermore, fuzzy model conducted integrate these weighted indices multi-criteria MD-GHP performance. Finally, proposed was applied practical four projects, returning scores 61.56, 58.33, 72.73, 78.41. These evaluations enable overall assessment MD-GHPs, technical weaknesses offering optimization guidance design operation.

Language: Английский

Citations

0