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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Measure Guideline: Condensing Boilers—Control Strategies for Optimizing Performance and Comfort in Residential Applications

The combination of a gas-fired condensing boiler with baseboard convectors and an indirect water heater has become a common option for high-efficiency residential space heating in cold climates. While there are many condensing boilers available on the market with rated efficiencies in the low to mid 90% efficient range, it is imperative to understand that if the control systems are not properly configured, these heaters will perform no better than their non-condensing counterparts. Based on previous research efforts, it is apparent that these types of systems are typically not designed and installed to achieve maximum efficiency (Arena 2010). It was found that there is a significant lack of information for contractors on how to configure the control systems to optimize overall efficiency. For example, there is little advice on selecting the best settings for the boiler reset curve or how to measure and set flow rates in the system to ensure that the return temperatures are low enough to promote condensing. It has also been observed that recovery from setback can be extremely slow and, at times, not achieved. Recovery can be affected by the outdoor reset control, the differential setting on the boiler and over-sizing of the boiler itself. This guide is intended for designers and installers of hydronic heating systems interested in maximizing the overall system efficiency of condensing boilers when coupled with baseboard convectors. It is applicable to new and retrofit applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Test Plan to Evaluate the Relationship Among IAQ, Comfort, Moisture, and Ventilation in Humid Climates

This experimental plan describes research being conducted by Pacific Northwest National Laboratory (PNNL), in coordinatation with Florida Solar Energy Center (FSEC), Florida HERO, and Lawrence Berkeley National Laboratory (LBNL) to evaluate the impact of ventilation rate on interior moisture levels, temperature distributions, and indoor air contaminant concentrations. Specifically, the research team will measure concentrations of indoor air contaminants, ventilation system flow rates, energy consumption, and temperature and relative humidity in ten homes in Gainesville, FL to characterize indoor pollutant levels and energy consumption associated with the observed ventilation rates. PNNL and FSEC have collaboratively prepared this experimental test plan, which describes background and context for the proposed study; the experimental design; specific monitoring points, including monitoring equipment, and sampling frequency; key research questions and the associated data analysis approach; experimental logistics, including schedule, milestones, and team member contact information; and clearly identifies the roles and responsibilities of each team in support of project objectives.

High Performance Homes↗
DOE OSTI2017

Review of Residential Comfort Control Products and Opportunities

This paper begins by discussing the interaction of each major component in advanced sensor and control applications related to HVAC equipment. The paper also looks at the applications of these components to commissioning, maintenance and operations of the HVAC equipment in residential buildings. A summary of state-of-the-art product features is also provided. These products are categorized through their primary application type (commissioning/maintenance or operation) and the features are categorized by component type (sensors, data storage, human-in-the-loop, communication, and controls). A common theme that emerges from this study is the importance of the ability for various product categories to be connected to each other. There are many manufacturers of sensors and many manufacturers of controls, but the power to automate any commissioning, maintenance or operation application, requires connectivity.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Research and Development of a Ventilation-Integrated Comfort System

From an indoor air quality perspective, the best residential ventilation strategies include filtering outdoor air and distributing that air to all occupied parts of a home. From an energy standpoint, it's desirable that energy be transferred from the exhaust air to the incoming outdoor air to limit heating and cooling impacts. Heat or energy recovery ventilation systems (HRVs or ERVs) can provide these functions, but researchers have seen many poor installations related to design, installation, and operation and maintenance. More robust ventilation systems may involve an ERV with a dedicated duct distribution system and controls. Such a duct system can be costly to install, and many builders reduce these costs by connecting an ERV to a central heating and cooling duct system. While this can sometimes be done effectively, researchers have seen consistent challenges with low, inconsistent, or imbalanced flow rates; high electricity consumption; and - of greatest concern - outdoor air short-circuiting or not being delivered to occupied spaces at all. Most ERVs are designed to operate with their own duct system; they are not designed as an add-on to much larger HVAC systems. With support from the US DOE Building Technologies Office, Steven Winter Associates, Inc. (SWA) partnered with Mitsubishi Electric Trane US, CORE Energy Recovery Solutions, and Therma-Stor LLC to design and test VICS prototypes. A conceptual diagram is shown in Figure 1, and the latest prototype (shown in Figure 2) was manufactured by Therma-Stor and tested in SWA's facility in Norwalk, CT. The ERV heat exchanger was provided by CORE, and the VICS was installed in conjunction with a 1-ton, inverter heat pump provided by Mitsubishi.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

Impact of Mass Wood Walls on Building Energy Use, Peak Demand, and Thermal Comfort

Thermal mass moderates indoor temperatures, allowing the heating, ventilation, and air conditioning (HVAC) system to operate more efficiently during peak hours. Cross-Laminated Timber (CLT) and other mass wood products provide thermal mass to the building envelope in a lighter and more environmentally friendly form than concrete. However, the influence of CLTs on heating and cooling energy, peak energy demand, and the indoor climate is not well-known. This project was formed to find the energy efficiency benefits of mass timber structures. The objectives were to (1) test the thermal performance of insulated mass wall structures in controlled laboratory conditions, (2) validate simulation models to expand performance to natural climatic conditions, (3) isolate the impact of the thermal properties of wood (thermal mass, thermal conductivity, moisture storage) on heating and cooling energy use and peak energy demand, and to optimize the performance. Currently, the designs used for CLT buildings have focused on structural and fire issues, and they do not consider the thermal mass benefits. Therefore, the thermal performance is not necessarily optimized.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Optimizing Hydronic Heating for Comfort and Performance in Multifamily Housing

Inefficient control settings in multifamily boilers often lead to substantial energy and cost penalties. To address this, a Fault Detection and Diagnostic (FDD) tool was developed to automate data analysis and identify operational faults such as suboptimal outdoor temperature sensor placement, misconfigured outdoor air reset (OAR) curves, excess boiler cycling, and domestic hot water (DHW) setpoint errors. By comparing pre- and post-implementation periods and applying engineering models, the tool quantifies energy savings and reduces manual analysis time by over 90%. Testing on over 100 monitored sites and a targeted subset of 12 buildings showed an average 11% energy savings from remote optimization; further validation across 19 OAR curve changes confirmed the tool’s accuracy, predicting actual savings within ±5% for most cases. Simple payback can be under three years for many multifamily buildings, though rising hardware, labor, and fuel costs create uncertainties, and decarbonization goals increasingly shift focus to electrification. The FDD tool remains invaluable for optimizing existing boilers, enhancing future electrification measures, and adapting to new technologies by refining building load estimates. In doing so, it supports both near-term efficiency and long-term transitions to low-carbon alternatives, ensuring buildings achieve substantial cost and energy benefits throughout their system lifecycles.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

R.U.N. Motion VR Boots: Realistic Unimpeded Natural (RUN) Motion Boots for VR gaming in the comfort of your home

Virtual reality (VR) gaming has experienced increasingly widespread adoption in recent years largely due to the development of affordable, consumer-grade headsets equipped with high quality, miniature displays and compact sensors for motion tracking. These devices are now able to provide users with immersive experiences that far surpass what traditional video games can achieve. However, despite these technological strides, a fundamental limitation remains: VR users are unable to move freely in their physical environment without the risk of colliding with real-world obstacles and hazards. This safety concern significantly restricts the level of immersion and natural movement possible in VR gaming.

42 ENGINEERING↗
DOE OSTI2023

The Impact of Operated Window Shading on Visual Comfort, Non-Visual Health, and Energy Demand from Electric Lighting

This paper introduces a simulation-based workflow to assess annual circadian lighting performance, glare risk and energy demand for an array of seated view positions under operated shading and electric lighting conditions. This workflow uses a combination of 9-band and 81-band simulations to represent daylight and electric lighting respectively. Annual daylight-driven calculations rely on a python-based code provided in the LARK simulation engine which was used to run 180-degree high dynamic range (HDR) renderings with 9-bands of spectral resolution. The results reveal the impact of shading systems on equivalent melanopic lux (EML) and daylight glare probability (DGP) over time and the energy demand (kWh) from electric lighting systems to supplement eye-level recommendations from the WELL v2 Building Standard.

Rockcastle, Siobhan↗
NASA NTRS1968

Concept to comfort-condition subjects wearing restrictive clothing

Heat exchanger maintains a desirable thermal balance in a subject wearing restrictive clothing. A grid of high thermal conductance fibers, in contact with the skin, transfers heat to or from the skin surface by means of a system of ducts, carrying the transfer fluid which is maintained at a controlled temperature.

Tucker, E. M.↗
NASA NTRS1972

Patient's breath controls comfort devices

Patient assist system for totally disabled persons was developed which permits a person, so paralyzed as to be unable to move, to activate by breathing, a call system to summon assistance, turn the page of a book, ajust his bed, or do any one of a number of other things. System consists of patient assist control and breath actuated switch.

Schrader, M.↗
NASA NTRS1971

Ride comfort control in large flexible aircraft

The problem of ameliorating the discomfort of passengers on a large air transport subject to flight disturbances is examined. The longitudinal dynamics of the aircraft, including effects of body flexing, are developed in terms of linear, constant coefficient differential equations in state variables. A cost functional, penalizing the rigid body displacements and flexure accelerations over the surface of the aircraft is formulated as a quadratic form. The resulting control problem, to minimize the cost subject to the state equation constraints, is of a class whose solutions are well known. The feedback gains for the optimal controller are calculated digitally, and the resulting autopilot is simulated on an analog computer and its performance evaluated.

Warren, M. E.↗
NASA NTRS1974

Environmental criteria for human comfort. A study of the related literature

The data presented has for the most part been extracted from existing in-house and memoranda reports. The variables considered are motion, noise, temperature and pressure. The report is broken down into chapters for each of the environmental variables and criteria proposed based on the existing literature.

Jacobson, I. D.↗
NASA NTRS1973

Effect of motion frequency spectrum on subjective comfort response

In order to model passenger reaction to present and future aircraft environments, it is necessary to obtain data in several ways. First, of course, is the gathering of environmental and passenger reaction data on commercial aircraft flights. In addition, detailed analyses of particular aspects of human reaction to the environment are best studied in a controllable experimental situation. Thus the use of simulators, both flight and ground based, is suggested. It is shown that there is a reasonably high probability that the low frequency end of the spectrum will not be necessary for simulation purposes. That is, the fidelity of any simulation which omits the very low frequency content will not yield results which differ significantly from the real environment. In addition, there does not appear to be significant differences between the responses obtained in the airborne simulator environment versus those obtained on commercial flights.

Jacobson, I. D.↗
NASA NTRS1974

Modular liquid-cooled helmet liner for thermal comfort

A modular liquid-cooled helmet liner made of eight form-fitting neoprene patches was constructed. The liner was integrated into the sweatband of an Army SPH-4 helicopter aircrew helmet. This assembly was tested on four subjects seated in a hot (47 C), humid (40%) environment. Results indicate a marked reduction in the rate of increase of physiological body functions. Rectal temperature, weight loss, heart rate, and strain indices are all reduced to approximately 50% of uncooled levels. The cooling liner removed from 10% to 30% of total metabolic heat produced. This study also demonstrated the technical feasilibity of using a cooling liner in conjunction with a standard hard helmet. Potential applications of the cooling liner in thermally stressful environments are numerous, notably for helicopter and other aircrews.

Williams, B. A.↗
NASA NTRS1975

Gust alleviation system to improve ride comfort of light airplanes

System consists of movable auxiliary aerodynamic sensors mounted on fuselage and connected to trailing-edge flaps by rigid mechanical linkages. System achieves alleviation by reducing lift-curve slope of airplane to such a small value that gust-induced angles of attack will result in small changes in lift.

Stewart, E. C.↗