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Verification and validation are crucial in developing and implementing models. Although there are standards to test energy simulation software, this article describes an additional set of eight test cases that are a combination of analytical cases and numerical cases for solid conduction heat transfer. These tests focus on diagnosing and verifying conductive heat transfer algorithms and boundary conditions in building envelopes or fabrics. As an example, EnergyPlus versions 5, 6 and 7 are tested using these eight test cases. The test cases were useful for detecting several bugs in the code. The authors recommend these test cases as useful complements to existing verification test cases for building envelopes.

This article describes the development, calibration and validation of a combustion-cogeneration model for whole-building simulation. As part of IEA Annex 42, we proposed a parametric model for studying residentialscale cogeneration systems based on both Stirling and internal combustion engines. The model can predict the fuel use, thermal output and electrical generation of a cogeneration device in response to changing loads, coolant temperatures and flow rates, and control strategies. The model is now implemented in the publicly-available EnergyPlus, ESP-r and TRNSYS building simulation programs. We vetted all three implementations using a comprehensive comparative testing suite, and validated the model's theoretical basis through comparison to measured data. The results demonstrate acceptable-to-excellent agreement, and suggest the model can be used with confidence when studying the energy performance of cogeneration equipment in non-condensing operation.

Most energy and load calculation procedures have assumed that room air is well mixed, which may lead to significant errors in sizing HVAC systems, estimating building energy use, and predicting thermal comfort for buildings with buoyancy-driven room airflow. This investigation has developed a framework and computer code for coupling detailed air models with building energy and load calculations as an extension to the ASHRAE Toolkit for Building Load Calculations. Two nodal models and a momentum-zonal model were selected for testing the coupling framework in a program for hourly load calculations of a single thermal zone. The heat balance model for load and energy calculations is reformulated to use zone air temperature as a variable defined separately for each surface. Air system flow rates are determined using air model predictions for temperature at the air system returns and a room air control location. The effect of air models on sensible load was found to be minor except when aggressive diurnal therm...

Building load and energy simulation programs based on the complete-mixing air model fail to consider the impact of nonuniform air temperature distributions. A momentum zonal model based on the Euler equation has been developed to enhance building load and energy simulations by predicting indoor airflows and temperatures. This paper shows some validation exercises by comparing model results to measurements and computational fluid dynamics. The model was found to predict thermal stratification conditions reasonably well and to err on the side of complete mixing. The model has been coupled to the heat balance model and tested on load calculations. Results for cooling and heating loads are compared to the traditional complete-mixing model with minor effects on total load but important differences in air system flow rate and control options. Total computation times for load calculations were two orders of magnitude higher using the momentum zonal model compared to traditional complete mixing.