scholarly journals Impact of Measurement Uncertainty on Building Modeling and Retrofitting Decisions

2021 ◽  
Vol 7 ◽  
Author(s):  
Mario Frei ◽  
Illias Hischier ◽  
Chirag Deb ◽  
Diego Sigrist ◽  
Arno Schlueter
Keyword(s):  
Measurement Uncertainty ◽  
Low Cost ◽  
Estimation Error ◽  
Measurement Data ◽  
District Heating ◽  
Heat Pumps ◽  
Wood Pellets ◽  
Building Stock ◽  
Building Retrofit ◽  
Measurement Uncertainties

Retrofitting buildings is essential for improving the existing global building stock. Innovations in wireless sensor networks have provided new means for scalable and potentially low-cost solutions for evaluating optimal retrofit measures in a building. Building models are used to explore different retrofit options and to find effective combinations of retrofit measures for a building in question. This paper departs outlining a novel grey-box modeling process for building retrofit based on measurement data. However, it is unknown if the measurement data and, as a consequence, the retrofit analysis is affected by uncertainties due to measurement accuracy and other factors. Quantifying these uncertainties during the analysis process is important in the context of making effective retrofit decisions. Consequently, this work examines the influence of measurement uncertainties on the generation of the retrofit models and the suggested retrofit measures. The results illustrate that measurement uncertainty is manageable for retrofit decisions, i.e., the measurement uncertainties rarely influence the ranking of retrofit measures. However, reduced measurement uncertainties are beneficial for adequately sizing the building retrofit interventions. It is shown that measurement uncertainty of flow meter measurements and indoor temperature measurements have the biggest impact on the heat loss coefficient estimation error, which ranges overall from 3 to 26%. Further, it is shown that some retrofit measures are more sensitive to uncertainty in the input data, such as district heating and wood pellets boilers, compared to measures that include heat pumps.

scholarly journals Assessment of the Equivalence of Low-Cost Sensors with the Reference Method in Measuring PM10 Concentration Using Selected Correction Functions

2020 ◽  
Vol 12 (13) ◽  
pp. 5368
Author(s):  
Tomasz Owczarek ◽  
Mariusz Rogulski ◽  
Piotr O. Czechowski
Keyword(s):  
Measurement Uncertainty ◽  
Low Cost ◽  
Measurement Data ◽  
Gravimetric Method ◽  
Reference Method ◽  
Testing Procedure ◽  
Coefficient Of Determination ◽  
Model Parameters ◽  
Equivalence Testing ◽  
Good Ability

The aim of the work is to demonstrate the possibility of building models to correct the results of measurements of particulate matter PM10 concentrations obtained using low-cost devices. Such devices apply the optical method to values comparable with those obtained using the reference gravimetric method. An additional goal is to show that the results corrected in this way can be used to carry out the procedure for testing equivalence of these methods. The study used generalized regression models (GRMs) to construct corrective functions. The constructed models were assessed using the coefficients of determination and the methodology of calculating the measurement uncertainty of the device. Measurement data from the two tested devices and the reference method were used to estimate model parameters. The measurement data were collected on a daily basis from 1 February to 30 June 2018 in Nowy Sącz. Regression allowed building multiple models with various functional forms and very promising statistical properties as well as good ability to describe the variability of reference measurements. These models also had very low values of measurement uncertainty. Of all the models constructed, a linear model using the original PM10 concentrations from the tested devices, air humidity, and wind speed was chosen as the most accurate and simplest model. Apart from the coefficient of determination, expanded relative uncertainty served as the measure of quality of the obtained model. Its small value, much lower than 25%, indicates that after correcting the results it is possible to carry out the equivalence testing procedure for the low-cost devices and confirm the equivalence of the tested method with the reference method.

scholarly journals Flexibility from Electric Boiler and Thermal Storage for Multi Energy System Interaction

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 98 ◽  
Author(s):  
Rakesh Sinha ◽  
Birgitte Bak-Jensen ◽  
Jayakrishnan Radhakrishna Pillai ◽  
Hamidreza Zareipour
Keyword(s):  
Curve Fitting ◽  
Estimation Error ◽  
District Heating ◽  
Thermal Storage ◽  
Energy System ◽  
Heat Pumps ◽  
Residential Area ◽  
Spot Price ◽  
Neural Net ◽  
Electric Boiler

Active use of heat accumulators in the thermal system has the potential for achieving flexibility in district heating with the power to heat (P2H) units, such as electric boilers (EB) and heat pumps. Thermal storage tanks can decouple demand and generation, enhancing accommodation of sustainable energy sources such as solar and wind. The overview of flexibility, using EB and storage, supported by investigating the nature of thermal demand in a Danish residential area, is presented in this paper. Based on the analysis, curve-fitting tools, such as neural net and similar day method, are trained to estimate the residential thermal demand. Utilizing the estimated demand and hourly market spot price of electricity, the operation of the EB is scheduled for storing and fulfilling demand and minimizing energy cost simultaneously. This demonstrates flexibility and controlling the EB integrated into a multi-energy system framework. Results show that the curve fitting tool is effectively suitable to acknowledge thermal demands of residential area based on the environmental factor as well as user behaviour. The thermal storage has the capability of operating as a flexible load to support P2H system as well as minimize the effect of estimation error in fulfilling actual thermal demand simultaneously.

scholarly journals A High Resolution Spatiotemporal Urban Heat Load Model for GB

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4078
Author(s):  
Salman Siddiqui ◽  
Mark Barrett ◽  
John Macadam
Keyword(s):  
High Resolution ◽  
Heat Load ◽  
District Heating ◽  
Temporal Variations ◽  
Heat Pumps ◽  
Building Stock ◽  
Load Model ◽  
Electrical Grid ◽  
Heat Demand ◽  
Urban Heat

The decarbonisation of heating in the United Kingdom is likely to entail both the mass adoption of heat pumps and widespread development of district heating infrastructure. Estimation of the spatially disaggregated heat demand is needed for both electrical distribution network with electrified heating and for the development of district heating. The temporal variation of heat demand is important when considering the operation of district heating, thermal energy storage and electrical grid storage. The difference between the national and urban heat demands profiles will vary due to the type and occupancy of buildings leading to temporal variations which have not been widely surveyed. This paper develops a high-resolution spatiotemporal heat load model for Great Britain (GB: England, Scotland a Wales) by identifying the appropriate datasets, archetype segmentation and characterisation for the domestic and nondomestic building stock. This is applied to a thermal model and calibrated on the local scale using gas consumption statistics. The annual GB heat demand was in close agreement with other estimates and the peak demand was 219 GWth. The urban heat demand was found to have a lower peak to trough ratio than the average national demand profile. This will have important implications for the uptake of heating technologies and design of district heating.

scholarly journals Measured performance of exhaust air heat pumps in Finnish apartment buildings

2021 ◽  
Vol 246 ◽  
pp. 06001
Author(s):  
Petri Pylsy ◽  
Jarek Kurnitski
Keyword(s):  
Heat Pump ◽  
Ventilation System ◽  
Measurement Data ◽  
District Heating ◽  
Energy Performance ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Apartment Buildings

The energy efficiency of existing apartment buildings is playing an important role in energy and climate targets. In Finland, mechanical exhaust ventilation system is commonly used in older apartment buildings. Hence, there could be an energy saving potential by an exhaust air heat pump system (EAHP). In this work two cases have been studied. Buildings were built in 1960’s and 1970’s and in renovation equipped with hybrid heating system: district heating and exhaust air heat pump system. Two years measurement data, 2018 and 2019, was collected to evaluate the performance of exhaust air heat pump systems. According to measurement data the monthly coefficient of performance (COP) was calculated as well as seasonal coefficient of performance (SCOP) was defined. The monthly COP values varied from 3,1 to 4,6 and SCOP values were about 3,7. Heating energy cost savings were 23-31 %. Energy performance class before and after EAHP installation was calculated. If at least 50 % of heating energy consumption was covered by EAHP then also energy performance class was improved.

The Utilization of Ground Source Heat Pumps (GSHP) for Research Purpose in the Campus of VSB - Technical University of Ostrava

2014 ◽  
Vol 1020 ◽  
pp. 507-512
Author(s):  
Petr Bujok ◽  
Martin Klempa ◽  
Michal Porzer ◽  
Antonín Kunz ◽  
Pavel Pospíšil ◽  
...  
Keyword(s):  
Measurement Data ◽  
District Heating ◽  
Primary Source ◽  
Cost Effective ◽  
Heat Pumps ◽  
Total Output ◽  
Ground Source Heat Pumps ◽  
Monitoring Wells ◽  
Deep Wells ◽  
Technical University

The largest been realized installations of heat pumps in the Czech Republic, where the primary collector of low-potential heat is formed deep wells, is heating complex building of new Auditorium and CIT in campus of VSB Technical University of Ostrava. This building represents two independent functional units (Auditorium with side halls and Information Technology Centre - CIT) with a total floor area of 9234 m2. The original project planned compound heating using district heating as a primary source of heat. Heating the object itself is a combination of floor heating systems and hot-air heaters. During project preparation has changed the project heating and a modern, technically unique and highly cost-effective solution has been designed with heat pump (type rock-water). Currently building heats 10 heat pumps with a total output of 700 kW through 110 wells with a depth of 130 m each. To assess the proportions of individual internal and external sources to the overall heat balance, the verification of systems designed for long-term monitoring of the behaviour of the rock massive around the energy used wells and energy storage options have been proposed and gradually implemented two research measuring polygons. They are located in the area of energy utilized wells. Each of the monitoring wells is instrumented with sensors at a certain depth. This article discusses the implementation of research polygons on experience with the excavation of wells using temperature sensors, a data acquisition system and finally outlines the possibilities of evaluating the measurement data.

scholarly journals Local Heating Networks with Waste Heat Utilization: Low or Medium Temperature Supply?

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 954 ◽  
Author(s):  
Hanne Kauko ◽  
Daniel Rohde ◽  
Armin Hafner
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Urban Areas ◽  
Waste Heat ◽  
Local Heating ◽  
District Heating ◽  
Heat Pumps ◽  
Hot Water ◽  
Local Network ◽  
Medium Temperature

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.

scholarly journals Business models combining heat pumps and district heating in buildings generate cost and emission savings

Energy ◽  
2021 ◽  
pp. 121202
Author(s):  
Kristina Lygnerud ◽  
Jonas Ottosson ◽  
Johan Kensby ◽  
Linnea Johansson
Keyword(s):  
Business Models ◽  
District Heating ◽  
Heat Pumps

scholarly journals Upgrading a District Heating System by Means of the Integration of Modular Heat Pumps, Geothermal Waters, and PVs for Resilient and Sustainable Urban Energy

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2347
Author(s):  
Elżbieta Hałaj ◽  
Jarosław Kotyza ◽  
Marek Hajto ◽  
Grzegorz Pełka ◽  
Wojciech Luboń ◽  
...  
Keyword(s):  
District Heating ◽  
Heating System ◽  
Upper Jurassic ◽  
Heat Pumps ◽  
Water Levels ◽  
Energy Potential ◽  
Geothermal Waters ◽  
District Heating System ◽  
Heating And Cooling ◽  
The City

Krakow has an extensive district heating network, which is approximately 900 km long. It is the second largest city in terms of the number of inhabitants in Poland, resulting in a high demand for energy—for both heating and cooling. The district heating of the city is based on coal. The paper presents the conception of using the available renewable sources to integrate them into the city’s heating system, increasing the flexibility of the system and its decentralization. An innovative solution of the use of hybrid, modular heat pumps with power dependent on the needs of customers in a given location and combining them with geothermal waters and photovoltaics is presented. The potential of deep geothermal waters is based on two reservoirs built of carbonate rocks, namely Devonian and Upper Jurassic, which mainly consist of dolomite and limestone. The theoretical potential of water intake equal to the nominal heating capacity of a geothermal installation is estimated at 3.3 and 2.0 MW, respectively. Shallow geothermal energy potential varies within the city, reflecting the complex geological structure of the city. Apart from typical borehole heat exchangers (BHEs), the shallower water levels may represent a significant potential source for both heating and cooling by means of water heat pumps. For the heating network, it has been proposed to use modular heat pumps with hybrid sources, which will allow for the flexible development of the network in places previously unavailable or unprofitable. In the case of balancing production and demand, a photovoltaic installation can be an effective and sufficient source of electricity that will cover the annual electricity demand generated by the heat pump installation, when it is used for both heating and cooling. The alternating demand of facilities for heating and cooling energy, caused by changes in the seasons, suggests potential for using seasonal cold and heat storage.

scholarly journals A Method for Optimizing and Spatially Distributing Heating Systems by Coupling an Urban Energy Simulation Platform and an Energy System Model

Resources ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 52
Author(s):  
Annette Steingrube ◽  
Keyu Bao ◽  
Stefan Wieland ◽  
Andrés Lalama ◽  
Pithon M. Kabiro ◽  
...  
Keyword(s):  
District Heating ◽  
Energy Systems ◽  
Energy System ◽  
Heat Pumps ◽  
Energy Simulation ◽  
Heating Systems ◽  
Optimal Amount ◽  
Urban City ◽  
Urban Energy ◽  
Building Level

District heating is seen as an important concept to decarbonize heating systems and meet climate mitigation goals. However, the decision related to where central heating is most viable is dependent on many different aspects, like heating densities or current heating structures. An urban energy simulation platform based on 3D building objects can improve the accuracy of energy demand calculation on building level, but lacks a system perspective. Energy system models help to find economically optimal solutions for entire energy systems, including the optimal amount of centrally supplied heat, but do not usually provide information on building level. Coupling both methods through a novel heating grid disaggregation algorithm, we propose a framework that does three things simultaneously: optimize energy systems that can comprise all demand sectors as well as sector coupling, assess the role of centralized heating in such optimized energy systems, and determine the layouts of supplying district heating grids with a spatial resolution on the street level. The algorithm is tested on two case studies; one, an urban city quarter, and the other, a rural town. In the urban city quarter, district heating is economically feasible in all scenarios. Using heat pumps in addition to CHPs increases the optimal amount of centrally supplied heat. In the rural quarter, central heat pumps guarantee the feasibility of district heating, while standalone CHPs are more expensive than decentral heating technologies.

ISO/TS 20914:2019 – a critical commentary

2020 ◽  
Vol 58 (8) ◽  
pp. 1182-1190 ◽  
Author(s):  
Ian Farrance ◽  
Robert Frenkel ◽  
Tony Badrick
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Data ◽  
International Normalized Ratio ◽  
Medical Laboratory ◽  
Uncertainty In Measurement ◽  
Medical Laboratories ◽  
Functional Relationships ◽  
Critical Commentary ◽  
Combined Uncertainty ◽  
Expression Of Uncertainty

AbstractThe long-anticipated ISO/TS 20914, Medical laboratories – Practical guidance for the estimation of measurement uncertainty, became publicly available in July 2019. This ISO document is intended as a guide for the practical application of estimating uncertainty in measurement (measurement uncertainty) in a medical laboratory. In some respects, the guide does indeed meet many of its stated objectives with numerous very detailed examples. Even though it is claimed that this ISO guide is based on the Evaluation of measurement data – Guide to the expression of uncertainty in measurement (GUM), JCGM 100:2008, it is with some concern that we believe several important statements and statistical procedures are incorrect, with others potentially misleading. The aim of this report is to highlight the major concerns which we have identified. In particular, we believe the following items require further comment: (1) The use of coefficient of variation and its potential for misuse requires clarification, (2) pooled variance and measurement uncertainty across changes in measuring conditions has been oversimplified and is potentially misleading, (3) uncertainty in the results of estimated glomerular filtration rate (eGFR) do not include all known uncertainties, (4) the international normalized ratio (INR) calculation is incorrect, (5) the treatment of bias uncertainty is considered problematic, (6) the rules for evaluating combined uncertainty in functional relationships are incomplete, and (7) specific concerns with some individual statements.

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