Evaluation of High-Rise Building-Based Hydroelectric Systems for Improving Energy Efficiency at the Urban Scale

This thesis assesses the potential benefits of implementing two alternative buildingbased hydroelectric technologies that have the capacity to improve energy efficiency at an urban scale.These technologies include a building-based hydroelectric system driven by wastewater, and the following two building-based hydroelectric energy storage systems: a pumped hydro system, and a gravity module system.An investigation is undertaken to analyze the techno-economic tradeoffs of each technology via the development of numerical models and their corresponding system scenarios.Results show that implementing a building-based wastewater hydroelectric system can offset the total annual pumping energy requirement by up to 36% regardless of the building's height, and that this system is cost effective when installed in buildings that have a minimum of 35 floors (roughly 105 m in height) and at least 47 units per floor.Regarding the two building-based hydroelectric energy storage systems, results show that the building-based gravity module system is capable of offering greater power capacity at a lower levelized electricity cost than the building-based pumped hydro system.The gravity module system can provide single-cycle storage capacities as high as 1,358 kWh in buildings that are 300 m tall.Moreover, this system, when used for energy storage purposes, has a lower levelized electricity cost than that of an equivalent lithium-ion battery system in all buildings exceeding 156 m in height.Nomenclature Symbols A Area of the base of the steel piston (m 2 ) 𝐶 𝑐 Capital cost ($) * 𝐶 𝑐𝑜 Capital cost of the concrete containment column ($)* 𝑐 𝑗 Annual operations and maintenance cost ($/yr) * 𝑐 𝐿𝐼𝐵𝑃 Annual variable system cost of lithium-ion battery plant ($/yr)* 𝑐 𝑚 Pump maintenance cost ($/MWh/yr)* 𝑐 𝑁𝐺𝑃𝑃 Annual variable system cost of natural gas power plant ($/yr)* 𝐶 𝑝 Capital cost of pumping system ($)* 𝑐 𝑝 Annual variable pump cost ($/yr)* 𝐶 𝑝𝑒 Capital cost of the penstock ($)* 𝐶 𝑟 Capital cost of pumped hydro reservoir ($)* 𝐶 𝑠 Capital cost of steel piston ($)* 𝐶 𝑠𝑒 Variable storage cost ($/kWh)* 𝐶 𝑡 Capital cost of turbine and electromechanical equipment ($)* 𝑐 𝑡 Annual variable turbine cost ($/yr)* 𝑑 Penstock diameter (m) 𝑑 𝑡𝑎𝑛𝑘 𝑜𝑢𝑡 Pipe diameter below the collection tank (m) 𝑑 𝑝𝑢𝑚𝑝 𝑃𝑍 Pipe diameter supplying pressure zone (m) 𝐸 𝑐𝑦𝑐𝑙𝑒 Energy cycle capacity (i.e., energy stored over a single cycle) (kWh) 𝐸 𝑝 Pump energy consumption per time step (Wh) 𝐸 𝑝 𝑎𝑛𝑛𝑢𝑎𝑙 Annual pumping energy consumption (kWh) 𝐸 𝑝𝑢𝑚𝑝 (𝑡) Energy used by the pumping system (kWh) 𝐸 𝑡 Turbine energy generation per timestep (Wh) 𝐸 𝑡 𝑎𝑛𝑛𝑢𝑎𝑙 Annual turbine energy generation (kWh) 𝐸 𝑡𝑢𝑟𝑏𝑖𝑛𝑒 (𝑡) Energy generated by the turbine-generator assembly (kWh) 𝑒 Pipe roughness (m) 𝑓 Friction factor 𝑓 𝑝𝑢𝑚𝑝 𝑃𝑍 (𝑡) Friction factor corresponding to pressure zone 𝑓 𝑡𝑎𝑛𝑘 𝑜𝑢𝑡 (𝑡) Friction factor corresponding to turbine system 𝑔 Gravitational constant (9.81 m 2 /s) H Equivalent gross head of water (m) ∆𝐻 𝑝 Total head for the pumping system (m) ∆𝐻 𝑝𝑢𝑚𝑝 (𝑡) Change in head of the pumping system (m) ∆𝐻 𝑝𝑢𝑚𝑝 𝑃𝑍 (𝑡) Change in head of pressure zone (m) ∆𝐻 𝑡 Total head for the turbine system (m) ∆𝐻 𝑡𝑢𝑟𝑏𝑖𝑛𝑒 Change in head of the turbine (m) 𝐻𝑅 Heat rate (GJ/kWh) 𝑖 Discount rate (%) 𝑗 Current year v 𝑘 Project Lifetime (yrs) L Length of penstock (m) msteel Mass of the steel piston (kg) mwater Mass of the volume of water equivalent to that of the steel piston (kg) ṁ Mass flow rate (kg/s) 𝑚̇𝑝 𝑢𝑚𝑝 𝑖𝑛 (𝑡) Mass flow rate of flow entering the building (kg/s) 𝑚̇𝑡 𝑎𝑛𝑘 𝑖𝑛 (𝑡) Mass flow rate of effluent entering the collection tank (kg/s) 𝑚̇𝑡 𝑎𝑛𝑘 𝑜𝑢𝑡 (𝑡) Mass flow rate of effluent exiting the collection tank (kg/s) 𝑁𝑠 Specific speed Chapter 2: Performance evaluation of a residential building-based hydroelectric system driven by wastewater .................

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.