Heat pump system assessment for a groundwater‐source municipal drinking water utility (original) (raw)
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Proceedings of the IGSHPA Research Track 2018, 2018
This case study discusses the field performance of a district central ground source heat pump (GSHP) system installed at Ball State University (BSU) in Muncie, IN., USA. This district GSHP system replaces the existing central steam plant and water-cooled chiller plants and designed to serve 47 major buildings in BSU. The field performance of the GSHP system was analyzed based on measured data from August 2015 through July 2016, construction drawings, maintenance records, personal communications, and construction costs. It was compared with the performance of a baseline scenario-a conventional water-cooled chiller and natural-gas-fired boiler system, both of which meet the minimum energy efficiencies allowed by the American Society of Heating, Refrigerating and AirConditioning Engineers (ASHRAE 90.1-2013). The comparison was made to determine source energy savings, energy cost savings, and CO2 emission reductions achieved by the GSHP system. This paper presents the results of the analysis, the lessons learned, and recommendations for improvement in the operation of this district central GSHP system.
Ground Source Heat Pumps: Considerations for Large Facilities in Massachusetts
2020
Ground-source heat pump (GSHP) systems have been implemented at large scales on several university campuses to provide heating and cooling. In this study, we test the idea that a GSHP system, as a replacement for an existing Combined Heat and Power (CHP) heating system coupled with conventional cooling systems, could reduce CO2 emissions, and provide a cost benefit to a university campus. We use the existing recorded annual heating and cooling loads supplied by the current system and an established technique of modeling the heat pumps and borehole heat exchangers (BHEs) using a TRNSYS model. The GSHP system is modeled to follow the parameters of industry standards and sized to provide an optimal balance of capital and operating costs. Results show that despite a decrease in heating and cooling energy usage and CO2 emissions are achieved, a significant increase in electric demand and purchased electricity result in an overall cost increase. These results highlight the need for therma...
Sustainable Energy Technologies and Assessments, 2020
Ground source heat pump (GSHP) systems can provide cost effective and sustainable heating and cooling for buildings while using considerably less fossil fuel than conventional heating and cooling systems. This benefit can be further enhanced by adopting hybrid GSHP (HGSHP) systems wherein the GSHP component provides the baseload thermal energy with the balance provided by conventional systems. This study compares the costs of GSHP and HGSHP systems against conventional systems under a variety of climatic conditions, exemplified by those encountered across Australia, but including conditions encountered elsewhere. The results indicate that the comparative performance of GSHP and HGSHP systems depend on many parameters including climatic conditions, ground conditions, drilling prices and prices of electricity and gas in the regions where the systems are installed. Here we show that in general, adopting GSHP or HGSHP systems over conventional systems allow property owners to pay lower lifetime costs under most climatic conditions and gas to electricity energy price ratios. The results also indicate that conventional systems may be preferred in highly heating or cooling dominant climates and at locations with high drilling costs or low energy prices. In contrast, GSHP and HGSHP systems are preferred in locations with a more balanced climate, lower drilling costs and/or higher energy prices. There is no "one size fits all" rule given the many factors that can influence the lifetime costs. The paper shows that climatic conditions, ground conditions, drilling and energy costs must all be carefully considered when assessing the most cost effective sustainable energy technologies for space heating and cooling.
Ground-source heat pump cooling systems in temperate cities. Case study: Mexico City
This paper addresses the viability analysis of using a ground-source heat pump (GSHP) system to supply part of the cooling requirements in an office building located in a city with temperate climate.The analysis includes the technical and economic feasibility, as well as the greenhouse gases emission reduction achieved by implementing this technology. The building used in this study has an annual electricity consumption of 2.7 GWh and a cooling space of 18000 m 2. The proposed system consists on the installation of a GSHP to complement the existent HVAC system. Total initial cost for this particular project implementation is around 1,193,000 MXN with an IRR on equity of 20%, a payback period of less than 8 years and a NPV of almost 4 million MXN. Moreover, annual savings were calculated to be over 2 million MXN with a Benefit-Cost ratio of 6.11. The cost of electricity has the greatest impact on the estimation of the NPV according to the risk analysis. Other benefits of implementing this system also include an annual greenhouse gas emission reduction of almost 61 tonnes of carbon dioxide, equivalent to savings of more than 26,000 litres of gasoline that would not be consumed.
Energy and Buildings, 2011
A multidisciplinary methodology is proposed for analyzing opportunities to use existing boreholes and an open-loop groundwater heat pump to provide summer cooling needs for large university buildings in Turin (NW Italy). The approach starts from a model of the buildings to determine the time profile of the cooling load. This curve is then coupled with a model of the off-design behaviour of the heat pump, which allows calculation of its energy performance (coefficient of performance, electricity consumption, etc.) as well as profiles of water discharge to the aquifer in terms of mass flow rate and temperature. Covering the peak energy needs of the buildings requires a variable amount of groundwater during the day. This could be provided varying the withdrawals from the aquifer but, as possible alternatives, two storage system solutions are examined: (1) chilled water storage and (2) groundwater storage. Simulations show that in both cases the use of storage systems produces environmental advantages, as the extent of the thermal plume reduces significantly. Moreover, chilled water storage presents a benefit in terms of reduced total primary energy consumption. The additional costs incurred by storage systems could necessitate public funding as well as system optimization.
Renewable Energy, 2015
In this study, the economic and environmental feasibility of air-to-air and geothermal heat pump systems is examined. The significance of the insulation level of the envelope on the economic and environmental feasibility of heat pump systems is demonstrated. The goal of this study is to quantify the extent to which the local climate and the building insulation level influences the economic and environmental feasibility of a geothermal water-to-air heat pump system and an external air-to-air heat pump system. In this study, the seasonal coefficient of performance SCOP is predicted for both heat pump systems for a residential building with varying insulation levels representative locations of the United States. The SCOP of both heat pump systems is calculated in a dynamic calculation process for use in a representative residential building with three different insulation levels of the building envelope. Results show a huge sensibility of SCOP values and feasibility studies towards the insulation level of the building envelope and the location.
36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 2023)
In this paper, the utilisation of groundwater heat pumps for residential heating and cooling purposes is presented. A case study located in Florence (Italy) is discussed. First, a building energy analysis has been performed to obtain the thermal loads. Then three heat pump systems (system 1: air-to-water, 2: groundwaterto-water, 3: surface water-to-water) have been designed and compared in terms of electric energy consumption, taking into account the dynamic changing of boundary conditions of the building. Finally, a Life Cycle Assessment analysis has been conducted to evaluate the environmental impacts of the systems. To ensure a yearly heating energy request of 2 780 kWh (peak load of 5 kW) and a yearly cooling energy request of 630 kWh (peak load of 4.4 kW) the systems present a yearly electricity consumption of 1 088 kW, 770 kW and 872 kW for system 1, 2 and 3 respectively. So the groundwater-to-water solution is the most efficient in terms of energy consumption. Based on LCA evaluation, system 2 is the environmentally less impacting system, with a Climate Change factor of 0.15 kg CO2 eq/kWh against the 0.21 kg CO2 eq/kWh of system 1. In terms of single score level, system 2 and system 3 are characterised by a reduction in impacts of about 24 % compared to system 1. The dynamic energy and LCA studies clearly show that the solution based on groundwater exploitation, in this context, is a very effective way to reduce electricity consumption and environmental impacts, confirming that the large-scale implementation of groundwater heat pump systems could be a promising option for the decarbonisation of residential heating and cooling sector.
Energy Performance Evaluation of a Recycled Water Heat Pump System in Cool and Dry Climate Zone
Proceedings of the IGSHPA Technical/Research Conference and Expo 2017, 2017
This paper presents performance evaluation results for a recycled water heat pump (RWHP) system, which uses the recycled water from a municipal water system as a heat sink and heat source for heat pumps. The temperature of the recycled water, system heat flow, and efficiency were analyzed based on measured data from December 2014 through August 2015. The annual energy consumption of the RWHP system was compared with that of a baseline system-a conventional variable-air-volume system using a water-cooled chiller and a natural gas-fired boiler, both of which meet the minimum energy efficiencies allowed by ASHRAE 90.1-2013. The analysis results indicate that, on an annual basis, the RWHP system has avoided 50% of source energy consumption, reduced CO2 emissions by 41%, and saved 34% in energy costs compared with the baseline system. This project is believed to be the first of its kind in the United States. The demonstrated technology, called recycled water heat pump (RWHP), has potential to be applied in other urban areas, given that there are existing RW distribution systems in many cities. For example, the existing RW system in Denver is over 70 miles long and is still expanding, and currently 171 water districts in 11 states in the United States have existing RW systems. Currently, the RW is mainly used for landscape irrigation and pond water-level management. This case study was conducted based on the available measured performance data from December 2014 through August 2015, utility bills for the building in 2014 and 2015, construction drawings, maintenance records, personal communications, and construction costs. The annual energy consumption of the RWHP system was compared with that of a baseline scenario-a conventional variable-air-volume (VAV) system using a water-cooled chiller and a natural gas-fired boiler, both of which meet the minimum energy efficiencies allowed by ASHRAE 90.1-2013 (ASHRAE 2013). The comparison was made to determine energy savings, operating cost savings, and CO2 emission reductions achieved by the RWHP system. A cost analysis was also performed to evaluate the simple payback of the RWHP system. More detailed information for this case study is given by Im and Liu (2015).
Energy Strategy Reviews, 2017
Geothermal resources have great potential as one of the sustainable energy strategies to provide reliable energy, since fossil fuel energy sources are limited, unreliable and will eventually be exhausted. The viability of geothermal heat pumps or ground source heat pumps (GSHPs) is significant as a potential alternative energy source with substantial savings potential. While the prospect of these systems is promising for energy efficiency, careful feasibility analysis is required before implementation. This paper presents the results of evaluation of the application feasibility for GSHPs in buildings across seven climate zones in three United States regions. A comprehensive methodology is developed to measure the integrated feasibility of GSHPs using compiled data for energy use intensity, energy cost and design parameters. Four different feasibility metrics are utilized: ground temperature, outdoor weather condition, energy savings potential, and cost benefits. For each metric, a corresponding feasibility score system is developed. The defined integrated feasibility score classifies the locations into five different feasibility levels ranging from Fair (0-20), Moderate (21-40), Good (41-60), High (61-80), and Very High (81-100). Conclusions show the GSHP feasibility level is High for 3 sites, Good for 8 sites and Moderate for 4 sites. Through the methodology, it is possible to develop practical energy strategy for more economic and sustainable GSHP systems at an early design stage in the various viewpoints of geometries, climate conditions, operational factors, and energy costs.
2015
— The energy use of a ground-source heat pump (GSP) for heating, cooling and hot water in a Central Pennsylvania residence (namely, the author’s house) is analyzed, compared to a simulation of electricity and a heating-oil furnace (with electric cooling) for these same energy uses. Energy demands for space conditioning in the house are simulated by building a model of the house using the Transient Energy System Simulation (TNRSYS) tool. Overall, the efficiency gain for the ground-source heat pump compared to electricity is 43 % for cooling and 81 % for heating. For home heating and hot water, the ground-source heat pump has a 42 % efficiency gain over a fuel-oil furnace. The system modeled in this paper has a payback period of between four and five years compared to an all-electric system. The payback period compared to a hybrid system of fuel-oil heat and electric cooling is between two and three years. Index Terms—Ground-source heat pump, energy efficiency, distributed energy I.